摘要:

The use of monoclinic ZrO2as an additive improves the mechanical properties of TiB2‐based composites without the use of stabilizers. In particular, TiB2‐30% ZrO2compacts exhibited a transverse rupture strength of 800 MN/m2, few pores, and a KIcof 5 MPa·m1/2. The high strength and toughness are thought to result mainly from the presence of partially stabilized tetragonal ZrO2and from solid solution of (TiZr)B2formed in sinte

ISSN:0002-7820    

DOI:10.1111/j.1151-2916.1985.tb15273.x

出版商:Blackwell Publishing Ltd    

年代:1985

数据来源: WILEY

摘要:

Alumina composites containing dispersed diamond particles were fabricated under very high pressure at a temperature where diamond is stable. Subsequent heat treatment in vacuum improves the toughness of the 5 vol% composite but not that of the 10 vol% composite. The heat treatment time was varied for both composites, and the influence of graphitization and morphology of the second‐phase particles on toughness were studie

ISSN:0002-7820    

DOI:10.1111/j.1151-2916.1985.tb15274.x

出版商:Blackwell Publishing Ltd    

年代:1985

数据来源: WILEY

摘要:

High‐density Si3N4ceramics with nitride additives such as TiN, AlN, ZrN, VN, NbN, YN, TUN, Mg3N2, and HfN were fabricated by isostatic hot‐pressing. The temperature dependence of Vickers microhardness, fracture toughness, and thermal conductivity were measured; these properties, as well as microstructure, were strongly influenced by the additive u

ISSN:0002-7820    

DOI:10.1111/j.1151-2916.1985.tb15275.x

出版商:Blackwell Publishing Ltd    

年代:1985

数据来源: WILEY

摘要:

The reaction of H2O2with alkoxides results in aerohydro gels of titania. These gels appear to form by a complex polymerization process involving peroxy species. The gels are porous and appear to have a fibrillar microstructure.

ISSN:0002-7820    

DOI:10.1111/j.1151-2916.1985.tb15276.x

出版商:Blackwell Publishing Ltd    

年代:1985

数据来源: WILEY

摘要:

The effect of adding BaCl2to BaSO4at elevated temperatures was studied. Differential thermal analysis and hot‐stage microscopy revealed that a eutectic occurs at 865°C between BaCl2and 13.5 mol% BaSO4. The microstructure in the reaction zone indicated that BaS04 recrystallizes from the eutectic melt. Thus, BaCl2additions can activate BaSO4at a temperature as low as 865

ISSN:0002-7820    

DOI:10.1111/j.1151-2916.1985.tb15277.x

出版商:Blackwell Publishing Ltd    

年代:1985

数据来源: WILEY

摘要:

A new compound, 5La2O3‐2Al2O3, is formed from an amorphous material prepared by the simultaneous hydrolysis of lanthanum and aluminurn alkoxides. It has an orthorhombic unit cell with a=0.9704 nm, b=0.5967 nm, and c=1.5473 nm. The structure contains tetrahedral AlO4groups and octahedral AlO6group

ISSN:0002-7820    

DOI:10.1111/j.1151-2916.1985.tb15278.x

出版商:Blackwell Publishing Ltd    

年代:1985

数据来源: WILEY

摘要:

The existence of eucryptite, spodumene, carnegieite, nepheline, and albite is very well known. To establish the phase diagram of the system LiAlSiO4‐NaAlSiO4‐SiO2, high‐SiO2equilibria and the sections LiAlSi2O6‐NaAlSi3O8, LiAlSi2O6‐NaAlSiO4, LiAlSiO4‐NaAlSiO4, and LiAlSiO4‐NaAlSi3O8were examined. The joins LiAlSi2O6‐NaAlSi3O8, LiAlSi2O6‐NaAlSiO4, and LiAlSiO4‐NaAlSiO4were established down to 800°C at

ISSN:0002-7820    

DOI:10.1111/j.1151-2916.1985.tb15279.x

出版商:Blackwell Publishing Ltd    

年代:1985

数据来源: WILEY

摘要:

To establish phase relations in the quaternary system Li2O‐Na2O‐Al2O3‐SiO2, the 50, 60, 70, 80, and 90 wt% isosilica planes were examined, mainly by quenching of quaternary glass composi

ISSN:0002-7820    

DOI:10.1111/j.1151-2916.1985.tb15280.x

出版商:Blackwell Publishing Ltd    

年代:1985

数据来源: WILEY

摘要:

The construction and utility of volatility diagrams – isothermal plots showing the partial pressures of two gaseous species in equilibrium with the several condensed phases possible in a system—are demonstrated for simple oxides with reference to the Mg‐0, A1‐0, and Si‐0 systems and compared with Ellingham‐type representations of these same data. Both types of diagrams are useful for providing a condensed format for a great deal of thermodynamic information. Their use is illustrated by analyzing the oxidation of Mg, Al, and Si and the volatilization of MgO, A12O3, and SiO2in both neutral and red

ISSN:0002-7820    

DOI:10.1111/j.1151-2916.1985.tb15264.x

出版商:Blackwell Publishing Ltd    

年代:1985

数据来源: WILEY

摘要:

Palmqvist crack extension in WC‐Co can be described using the center‐loaded penny crack analogy. When Palmqvist cracks are represented by semicircles of diameter l (l=crack length measured from an impression corner), the stress intensity factor which controls crack extension differs from that of a half‐penny crack of radius l+a (2a = impression size) by only a slowly varying factor m=21/2(l/a)1/2; m≅1.0 to 2.4 for WC‐Co and m≅0.8 to 1.4 f

ISSN:0002-7820    

DOI:10.1111/j.1151-2916.1985.tb15281.x

出版商:Blackwell Publishing Ltd    

年代:1985

数据来源: WILEY