The synthesis of superhard materials is an interesting research subject in the field of materials
science. Recently, experimental and theoretical research activities on materials with an hardness comparable to or higher than diamond have
been stimulated by the postulation and discovery of novel carbon- and boron-based superhard materials. Besides diamond and c-BN, β-C₃N₄,
c-BCN and fullerenes are also potential candidates for superhard materials. This review deals with the latest research progress in the field of novel carbon- and boron-based superhard materials.

It is significant to research the growth defects of KTiOAsO₄ crystal in order to improve its physical properties and applications. The growth defects of KTA were studied by the methods of optical micrography and synchrotron radiation topography. The result indicates that two kinds of etchant produce a marked effect to show the defects of KTA crystal, and the main defects in KTA crystal are ferroelectric domain, growth striation, sector boundary, dislocation and inclusion. The forming cause of the defects was also discussed.

The different growth unites of two polymorph antimony white were analyzed and determined according to the theoretical model of growth units with coordination polyhedron structure of anion, and the chajnge characteristic of the polymorph structure of antimony white prepared by hydrolysis was discussed in detail, and the polymorph control mechanism of antimony white powders prepared by hydrolysis was revealed.

The quantificational relationship between EPR zero-field splitting parameter D and structure parameters of
Cr³⁺ vacancy centre in CsCdF₃:Cr³⁺ crystals was established according to the superposition model and third-order perturbation theory. The
existence of Cd²⁺ vacancy and the lattice distortion were verified. Meanwhile, F^- ion moving toward the central Cr³⁺ ion by X₁=0.00291nm,
X₂=0.001nm, X₃=0.00262nm was obtained. Good agreement between the theoretical results and the experimental values shows that the assumption of
the Cd²⁺ vacancy and the lattice distortion is reasonable. Although the main of source of the tetragonal crystal field comes from the Cd²⁺
vacancy caused by the charge compensation, the contribution of the lattice distortion can not be neglected.

The standard Gibbs free energy of Ti₂O was predicted according to the quasi-parabola rule.
The co-existing region of Ti and ZrO₂ was obtained by thermodynamic calculation to determine the synthesis conditions of this composite.
ZrO₂-Ti system composites sintered under ordinary pressure were prepared by a powder metallurgical method. The gradient distribution of
composition, the interfacial microstructure between layers and the combining state of phases between Ti and ZrO₂ were investigated by means of
XRD, SEM, EDS, TEM and so on. The experimental results show that the joint between Ti and ZrO₂ phases is physical in this composite. ZrO₂ mainly
exists as a tetragonal phase.

The processing of synthesizing nano Y-TZP materials by hot-pressing was investigated. It was found that there were large crack-like pores in the sintered samples. The
reason of this new phenomena was that the soft agglomerate in the powder was not efficiently destroyed. When sintered, the soft agglomerate sintered quickly
and turned into hard agglomerate, as a result of the interaction between the hard agglomerate and the matrix, large pores formed. On the other hand, the applied
pressure was limited because the low stress tolerance of the graphite die, so no plastic displacement could happen and those large pores could not be "squashed",
As a result, the density of the samples sintered by hot-pressing was lower than that by pressureless sintering at the same sintering temperature. To overcome this
shortage of hot-pressing, sinter-forging was applied and nano Y-TZP materials with grain size of about 85nm and relative density of 99% could be obtained when sintered at 1100℃.

β-Sialon/corundum composite refractories were prepared by using Al, Si metal powders, Al₂O₃ fine powder, and corundum aggregates as raw materials at
the temperatures lower than 1600℃by nitridation sintering process. It shows that β-Sialon (Si_6-zAl_zO_zN_8-z, corundum, 15R
phase appear in all the resultant products different in the contents of β-Sialon, 15R and the Z value of β-Sialon, even though only β-Sialon and corundum
phases are expected in designed materials. And the Z value of the produced β-Sialon is deviated from the designed value. Such facts were supposed to
be related to the reaction progress. Additionally, these β-Sialon/corundum composite refractories were tested by alkali, molten slag and steel. The results
show that composite refractories of β-Sialon with Z=1.5～2.5 have good alkali resistance and all of the composite refractories have good molten slag and steel resistance.

Aluminium nitride ceramics were successfully fabricated through low-temperature sintering by using (YCa)F₃ as the sintering aid. AIN ceramics with a high thermal conductivity of 208W/m·K were obtained after the specimen was sintered at 1650℃ for 6h. Calculation based on the present and reported results led to an equation which describes the dependence of thermal conductivity of AIN on the soaking time in sintering: λ(t) =λ_∞ -△λ(0)·e^-t/r. SEM, TEM, SThM and HREM were employed to study, the microstructure-property relationship of AlN ceramics. It was concluded that AlN grain sizes
have little effect on the thermal conductivity, while grain boundary phases deteriorate thermal conductivity.

Compact AlN-TiC ceramics were fabricated by combustion synthesis of Al particles in
super-high pressure nitrogen (100MPa), and the maximal relative density of 95% can be gained in the products, and maximal bending strength reached
240 MPa. In the SHS process of Al-N₂-TiC system, when the temperature was up to 660℃, Al melted. At high temperature of SHS
reaction melting, Al spread over TiC particle surfaces, which led to liquid sinter occur in the SHS reaction zone. With liquid sinter occurred,
the porosity of reaction zone apparently decreased. With increasing of TiC content in the original powder system, liquid sintering strengthened,
and relative density of the products improved, bending strength and fracture toughness increased. In Al-N₂-TiC system, SHS-densification
had apparent tropism, mainly occurred along the combustion front.

The growing process of AIN crystal in directed nitridation of molten aluminium alloys was investigated. The growing characters of AIN crystals were obtained through XRD and SEM. A new mechanism of vapour-liquid-solid-solid (VLSS) was proposed, and its similarity and difference from the traditional vapour-liquid-solid (VLS) mechanism were discussed. The emphasis was placed on the prerequisites and realization process of VLSS mechanism

A novel synthesis of the large tunnel structure Mg-containing Todorokite from nano6-MnO₂ and 3mol/L MgCl₂ in a higher pressure caldron was described. XRD and TEM results confirm that Mg-Todorokite is also a nano-phase MnO₂ with homogeneous particle size. Electrochemical studies on constant current discharge and cyclic behavior of Mg-Todorokite in 9mol/L KOH or in 5mol/L LiNO₃ aqueous electrolytes show that it possesses a lower open circuit voltage, and a good cycling performance.

Cu-Cu₂O eutectic bonding of copper to Al₂O₃ was investigated. The highest peel strength was 11.5kg/cm for the specimen prepared at 1070℃ for 3h in nitrogen atmosphere. Oxygen promoted the wetting between
copper and Al₂O₃ greatly. Cu[O] melt reacted with the alumina and formed a continuous CuAlO₂ layer, which enhanced the peel strength of the joint. On
cooling, the solidification front moved from the solid copper towards alumina, and Cu₂O precipitated from the Cu[O] melt. When the solidification front met
the CuAlO₂ layer, liquid-aided reaction completed and a reliable bond was achieved between the copper and Al₂O₃ substrate.

Titanium porous clays were synthesized by the reaction of Na-montmorillonite with Ti crosslinking agent prepared by sol-gel method. The preparation conditions of
titanium porous clay were also researched by means of XRD, IR and DTA etc. The results show that the product synthesized by sol-gel method is easy to form large
pore structure than by TiCl₄ hydrolysis method, the resulting titanium porous clay possesses interlayer free spacing of 2.93nm and surface area of 351.0m²·g^-1
with the preparation condition of [Ti]=0.82mol·L^-1, [Ti]/clay=20mmol·g^-1, and has a good thermal stability to 860℃.

The dynamic corrosion rate of six commercial refractories was measured in the iron phosphate melts containing simulated HLW and a borosilicate melt (DWPF) at
temperatures from 1000 to 1300℃. A dense alumina and a chrome refractory had the lowest melt-line corrosion rate in the iron phosphate melts, whereas the
corrosion rate for silica, zircon, and alumina-zirconia-silica(AZS) refractories was somewhat high. In general, the corrosion rate for the alumina and chrome refractory
in the iron phosphate melts was no higher than their corrosion rate in the DWPF melt now used at the Savannah River Site. For the chrome refractory, the corrosion
rate in three iron phosphate melts containing simulated HLW waste was under 0.1mm/day at the melt line. It is concluded that commercially manufactured, dense alumina
or chrome refractories can be acceptable for melting many iron phosphate composition, even in wastes containing up to 16 weight percent soda.

A kind of Co_xR_1-xAl₂O₄(R=Zn、Mg，x=0.8\sim1.0)cobalt blue pigment suitable for luminophor of color televisions was synthesized successfully by
using the chemical coprecipitation method. Compared with CoAl₂O₄ reflectivity, the increase of reflectivity of Co_xR_1-xAl₂O₄ is 18.2% at 450nm
and --5% at 600nm respectively. Through discussing some affecting factors on this kind of pigment such as doping cation type, doping content and Co²⁺
content, a conclusion can be drawn that the mechanism of reflectivity properties alteration of complex cobalt blue pigments caused by doping cations Zn²⁺,
Mg²⁺ is Co²⁺3d electronic energy level cleavage due to lattice distortion. The lower limit value of x of Zn²⁺, Mg²⁺ is 0.85 and 0.8 respectively.

The effects of Cu content and density of powder compacts on the features and velocity of the combustion wave during its propagation through the bi-layered powder compacts of (Ti-2B-
60wt%Cu)/(3Ti-2BN-xCu) (x=0, 10, 20, 40wt%) were investigated. The combustion wave velocity for specimen (3Ti-2BN), (3Ti-2BN-10wt%Cu), (3Ti-2BN-20wt%Cu) and (Ti-2B-
60wt%Cu) compacted with pressure p=60MPa is 4.96, 4.43, 2.17 and 18.52mm/s respectively. While, combustion wave cannot propagate through the specimen of (3Ti-2BN-40wt%Cu). In (Ti-
2B-60wt%Cu)/(3Ti-2BN-x·Cu) bi-layered system, the features of the combustion wave change from bending toward the (3Ti-2BN-x·Cu) layer to cutting as wedge-shape to this layer as the x
increased. Besides, the effects of green densities of specimens compacted with p=12, 24, 84, 108MPa on the feature and combustion wave velocity were investigated.

The factors that have influence on structure and electrical properties of hot pressed
0.3PZN-0.7PZT piezoelectric ceramics，such as Pb content，pressure，annealing temperature and time，were investigated. The results show
that the factors of Pb content, annealing temperature and annealing time have big influence on the properties of hot-pressed 0.3PZN-0.7PZT
piezoelectric ceramics. With Pb content of 98.5%, annealing temperature of 1250℃ and annealing time of 7 hours, the piezoelectric
properties, d₃₃=715pC/N，K_p=0.65，tgδ=2.9%，ε_r=3457，Q_m=50.1. High-density ceramics (99.8% of theoretical value) can be obtained with the hot pressing
and annealing method.

90° Ferroelectric domains in 67 Pb(Mg_1/3Nb_2/3) O₃-33PbTiO₃ single crystal were observed at room temperature by using crossed polarized light microscope(PLM). Ferroelectric domain structures depend on the quality of
single crystals. Large homogeneous domains of 2～3mm exist in optical transparent single crystals. Large domains with different polarization
orientation overlap to form opaque regions. {110} type 90° banded a-a domain with 90° sub-domain can be observed in translucent
crystals. The dimension of banded twin is about 0.1mm. As a result, surface relief appears on translucent crystal surface. The mechanism of forming
these domains was discussed.

Unusual increase of displacement in special ring type piezoelectric ceramic actuators with transverse mode was found, which were made from three discrete
actuators using piezoelectric ceramics with tungsten bronze structure. The increasing values of displacement were as high as about 30%, as
compared with the composing discrete one. The discrete actuators are in press stress according to analyses and experiments, and the unusual
phenomenon is related to their stress condition. This mechanism can be described as follows: under the press stress the spontaneous polarization
P_s will departure from original direction (the pressure direction), due to some 90° domains reorientation or some distortion of oxygen-
octahedras in tungsten bronze structure, then as soon as electrical field E is applied, the P_s will return the original directions, that leads to
the increment of strain for the ring type actuator.

Positive Temperature Coefficient of Resistivity (PTCR) materials based on Yttrium and Yttrium Fluoride (YF₃) doped Barium titanate (BaTiO₃) ceramics were prepared in different sintering atmospheres, respectively. The effects of
sintering atmospheres on the microstructure, property and mechanism of substitution of doped BaTiO₃ ceramics were investigated by the means of XRD, SEM, XRF
and R-T measuring instrument. Sintering in a low oxygen partial atmosphere can increase the densities of Y and YF₃ doped BaTiO₃ and make grain particle
grow. Both Y and YF₃ doped BaTiO₃ ceramics are n-type semiconductor in which Y substitutes A-site and F substitutes O-site. Sintered in a argon
atmosphere, Y doped BaTiO₃ exhibited little PTCR effect, however, an anomalous PTCR effect was observed when 0.3mol% YF₃doped BaTiO₃ ceramics was fired
in Argon atmosphere. This phenomenon may be explained by a new O site substitution mechanism.

Semiconducting BaTiO₃ and high-curie-point (Ba_0.4Pb_0.6)TiO₃ PTCR ceramics added with BN as a super low temperature sintering aid were investigated, and
the function of BN on the liquid-phase sintering of PTCR ceramics was studied. In comparison with AST and Si₃N₄, BN is a more effective additive that can
not only reduce the sintering temperature but also widen firing range. La-doped BaTiO₃ ceramics with BN addition can be obtained at 1100℃. The sintered
sample shows the PTC effect of 4.9 orders of magnitude and resistivity of 150Ω·cm. Nb-doped (Ba_0.4Pb_0.6)TiO₃ PTCR ceramics with the high Curie point
of 360℃, added with BN and AST, can be sintered at 1000℃. The super low temperature sintering for the PTCR ceramics has not been reported before.

β-Al₂O₃ powdered material could be prepared from the mixtures of Li₂CO₃, Na₂CO₃
and Al₂O₃, which were obtained by dry mixing, wet mix-screening or spray-drying process, by stepped calculating without grinding. The effect
of preparation condition on the properties of the powdered material was showed. The powder composed of β/β’’-Al₂O₃ in principle, f(β’’)>70%, could be fabricated into solid electrolytic
coating for metal pipeline in atmosphere, with some binders and solvents. The powder in the coating was stable chemically and electrochemically to metal, binders and
moistur. The polarization behavior of cathode for “Beta-coating” showed that there was a flat at the polarization curve, which could be evaluated for the cathode protection of metal in atmosphere.

The materials were prepared by coating the phenol formaldehyde resin on the surface of the natural flake graphite (NFG) powders using liquid-phase-
impregnation and pyrolysis. The charging-discharging performance of the materials used as the negative electrode for lithium ion batteries in
1M LiPF₆/EC+DEC(1:1) electrolyte solution was investigated by means of the galvanostatic charging-discharging experiments and the cyclic
voltammetry experiments. The influence of different heat treatment temperatures (HTT) on the charging-discharging behaviour of the materials
was discussed. The results show that the charging-discharging characteristics of the material heat-treated under 900℃ are as
follows: the third stable discharging capacity(D₃) is 213.75mA·h/g, the third cycling efficiency (η₃) is 88.69%, and the cycling
life is long. It can be used as the negative electrode for the high-performance lithium ion batteries.

iCN films were prepared by RF magnetron sputtering with SiC target. The influences of the basic
process parameters, such as the deposition power and partial pressure of nitrogen, on the deposition rate and optical properties were studied.
XPS and FTIR results revealed the formation of a complex network among Si, C and N. The deposition rate decreased with increasing partial
pressure of nitrogen. The increase of N flux resulted in wider optical gap. The higher the deposition power, the higher the deposition rate
and the narrower the optical band gap.

ZrO₂ and ZrO₂:CdS films were synthesized by sol-gel technique using re-crystallized ZrOCl₂·8H₂O as the starting material. The results show
that the concentration of ZrO₂ and thickness of films can influence the transmission property of ZrO₂ films. CdS nanoparticles can be well dispersed
in ZrO₂ film. The average size of CdS particles is 4～6 nm. The conclusion is: (1) the crystallization of ZrO₂ particles can influence the optical properties
and surface morphology of ZrO₂ films; (2) CdS nanoparticles incorporated in ZrO₂ films can restrain the crystallization of ZrO₂ and relatively smooth
ZrO₂:CdS film can be obtained.

The Eu³⁺ ion doped SiO₂ aerogel film was prepared by a sol-gel process, and the luminescence and transitions of this aerogel film were investigated. The surface structure of the film was observed by AFM. Its microstructure was investigated
by XRD and IR. Its excitation, emission, absorption, and time-resolved spectra were measured. The luminescence properties were discussed. The radiative transition
probabilities of ⁵D₀ energy levels in Eu³⁺ ion were calculated by Judd-Ofelt theory. According to the time-resolved spectra, the nonradiative transition probabilities
and decay properties of ⁵D₁ were also studied. The results are not quite different to Eu³⁺ ion in silicate glass, but a fine thin film doped with rare earth ions
can be obtained by using a facile and low temperature method, and this film, having luminescent light glass qualities, can possess potential applications.

Iridium oxide (IrO₂) thin films were successfully grown on SiO₂/Si(100) substrate by a DC magnetron reactive sputtering method with an Ir target(99.9% purity).
PZT ferroelectric thin films were deposited by a sol-gel method. The as-deposited thin films were annealed with a thermal annealing process, after that the films
were highly directed at (110) or (200). The effect of sputtering parameters such as gun power, oxygen partial pressure (Ar/O₂) and growth temperature
and annealing conditions on the crystalline nature and morphology of IrO₂ thin films was discussed.

The Cr-N coating/AISI52100 substrate bonding strength with different dynamic recoiling intermixing processes were evaluated by Rockwell-R
adhesion (P_c) and spherical rolling contact fatigue tests. The results show the coatings are of an excellent bonding strength
at low bombarding energy of 10keV and 20keV N ion dynamic recoiling intermixing. With bombarding energy increasing from 10keV and 20keV
to 40keV, the Rockwell-R adhesion (P_c) is 650N, 700N and 330N, and fatigue life (Δτ_rz=442MPa) decreases from 5.0×10⁶ to 9.0×10⁵. The results of P_c
and spherical rolling contact fatigue strength possess resemble tendency.

Potassium lithium niobate single crystals of 10mm in diameter and up to 45mm in length were grown by the modified Bridgman technique. The transmittance spectrum and dielectric property of as-grown crystal were measured. The wafer of as-grown KLN crystal has good transmittance from 400nm to 800nm. Dielectric constants ε₃₃ and ε₁₁) at room temperature are 127 and 376 respectively. The cleavage face and chemical inhomogeneity are the main factors of cracking.

FTIR absorption spectra and XRD were used to study the structure of glasses using red mud as raw
materials. The results indicate that Ca(Fe, Mg)Si₂O₆ and 2CaO·Al₂O₃·SiO₂ precipitate as primary and minor crystalline
phase respectively on crystallization processes of glasses. Glasses have interlinked SiO₄, AlO₄ and Fe³⁺O₄ tetrahedra as their most
fundamental units with K⁺, Na⁺, Fe²⁺ and some Fe³⁺ ions acting as charge balancing cations. The short-range order which is similar
to the structure of Ca(Fe, Mg)Si₂O₆ exists in the glasses and has the precursor structures of primary crystalline phase. With the increase
of Fe₂O₃ content, the random state of glass structure increases. The absorption bands of FTIR spectra become broaden and shift from the high
frequency region to lower frequencies. With prolonging nucleation time and improving crystallization temperature, the strongest absorption bands also
shift from the high frequency region to lower frequencies.

Based on our previous study on formation and densification behavior of AlN-polytypoids(15R, 12H, 21R)^[1],
their mechanical properties and microstructure were studied. The results show that the AlN-polytypoid phases possess relatively poor mechanical
properties, however, their flexural strength can remain constant(21R) or increase as high as 50%(15R and 12H) from room temperature till 1250℃.
The hardness varies with the species of AlN-polytypoids and the additives used in a range of 11.5～14.4GPa(H_v10). The 15R compositions
possess the lowest hardness varying from 11.5 to 12.8GPa. For 12H and 21R compositions, the varying range increases to 12.6～13.8GPa and
12.7～14.4GPa, respectively. The longer stacking sequence in AlN-rich polytypoids is responsible for its higher hardness because of the longer
Burgers vector required for slip dislocations. The fracture toughness and flexural strength has no such close relationships to the type of AlN-
polytypoids. They varied in the range of 3.8～4.8MPa·m^1/2 and 313～366MPa, respectively. The pull out and micro-cracks formed
in the AlN-polytypoids grains are supposedly the main mechanisms for the strengthening effect at high temperature.

Nanosized anatase titania colloid and powders were prepared by hydrolysis of titaniumtetrabutoxide in basic media and then dehydrated at 700C in acid media. The powder and colloid were characterized by XRD、 BET、 TEM、 HREM and TG-DTA methods. The results show that after dehydrated in acid media the titania particles in colloid are already anatase crystallites with good crystal lattices. The average diameter of the nanosized titania powder after calcination at 220℃ is 9nm and surface area is 171m²/g.

The preferential orientations of aragonite crystals in nacre of shells are considered to be one of the most important reasons responsible for high
mechanical performance of nacre. Based on the X-ray diffraction analysis, the preferential orientations of aragonite crystals in nacre from shells of main
pearl-cultivating molluscs of China were systematically studied. It shows that 1): in nacre of Pinctada martensii (Dunker), Pinctada maxima (Jameson), Peteria
penguin (Roding) the c axis of aragonite crystals is all perpendicular to nacreous layers; 2):?in nacre of Hyriopsis cuningii (Lea) shell, there exist two kinds of orientation,
one is the c axis of aragonite perpendicular to nacreous layers, the second is inclined to nacreous layers, i. e. (012) net of aragonite lattice is parallel to nacreous layers.