Y.W.Yan1)
,
B.K.Wei2)
,
Z.Y.Fu1)
,
H.T.Lin2) and R.Z.Yuan1) 1) State Key Lab .of Advanced Technologyfor Materials Synthesisand Processing
,
Wuhan University of Technol ogy
,
Wuhan 430070
,
China 2) Institute of Materials
,
Huazhong University of Science and Technology
,
Wuhan 430074
,
China
金属学报(英文版)
Under aircondition,theinsitu TiCP/ Fecompositeshavebeen fabricated by a reactivecast ing route usingtheinexpensiveraw materials. The microstructuresofthecompositehavebeen studied by X ray diffraction,image analyzer and analyticalelectron microscopy. The me chanicalpropertiesand abrasive wearresistanceofboththeas castcompositeandthequenched composite havebeen measured. Theresultsshow thattheinsitu TiCparticles with a average sizeof 4 51μm exhibit a homogenous distribution inthe matrix, and an excellentinterface bonding between the particle and the matrix is achieved. As above microstructure features, thecomposite,especiallythequenched composite, hashigher mechanicalpropertiesand betterwear resistance,compared with high Cr whitecastiron.
关键词:
TiCP/ Fecomposite
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Z.M.Xu1)
,
J.S.Zhen1)
,
H.F.Liu1) and L.M.Zhang2) 1)Departent of Chemistry
,
Huazhong University of Science and Technology
,
Wuhan 430074
,
China 2)Institute of Materials Science and Engineering
,
Wuhan University of Technology
,
Wuhan 430070
,
China
金属学报(英文版)
Thispaper proposed a new methodof producing Ceramic/ Metalfunctionally gradient mate rialby electroless platingtechnique. The experimentof producing SiC/ Ni PFGM wascar ried out with self made electroless plating facilities. The results show that the thickness of FGMcoating andthegradientdistribution ofcompositioncanbecontrolled byoptimizingelec trolessplating technology and changing the parameters such as plating time, the additionspeed and concentration of SiCparticles. Analysisdemonstratesthatthereisastrongrelation ship amongthe SiCcontent,the microstructureandthe mechanicalproperty ofthe FGM.
关键词:
electrolessplating
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J.Y. Zhang
,
Z.Y. Fu
,
W.M Wang
,
H. Wang and X.M. Min State Key Lab .of Advanced Technologyfor Materials Synthesis and Processing
,
Wuhan University of Technolo gy
,
Wuhan 430070
,
China
金属学报(英文版)
Self consistent Field discrete variational Xα( SCF Xα DV) method was used to study the wettabilitybetween TiB2 Ceramic and Metals. The Metals were Ni, Mo, Ni+ Mo, and etc. microstructureof TiB2/ Fe, TiB2/ Niand TiB2/ NiMoinvestigatedby TEM werechosen toidentify the calculation model. The result shows the wetting in the above systems were chemicalreactive wetting ,and can becalculated by SCF Xα DV . Theeffectof active ele ment( Mo) to TiB2/ Ni wettability wasstudied too.
关键词:
wetting
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X.M.Min
,
C.W.Nan and K.F.Cai National Key Laboratory of Advanced Technology for Materials Synthesis and Processing
,
Wuhan University ofTechnology
,
Wuhan 430070
,
China
金属学报(英文版)
Thecorrelation between composition, structure, chemical bond, and thermoelectric proper tiesof Si doped boroncarbidesisstudied using SCF DV Xαmethod. Thecalculationsshow that Siatom firstlysubstitutes Bor Catomson theend of boron carbidechain, then may occupyinterstitialsites when Siis dopedin boron carbide, anditisdifficultfor SitosubstituteBor Catom in thecenter of chain orintheicosahedron. Arepresentativestructural unitcontain ing an Si atom is 〔C B Si〕ε+ 〔B11 C〕ε , whilethe structural unit without Siis 〔C B B ( C)〕δ 〔B11 C〕δ+ . Afteradding Sitotheboroncarbides,theenergyrequired bythe dispro portionation reaction decreases,theconcentrationofthecarriersincreases,andthereare more pathsfor the bipolaron to hopping. At thesametime, the covalent bond becomes weaker, andthethermal conductivity decreases. Therefore, thethermoelectric property of Si dopedboron carbidesisimproved .
关键词:
Si doped boroncarbide
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X.M.Min
,
Y. Daiand C.W.Nan National Key Laboratory of Advanced Technology for Materials Synthesis and Processing
,
Wuhan University ofTechnology
,
Wuhan 430070
,
China
金属学报(英文版)
Al NMRand quantum chemistry calculation have been used to study thestructureof γ Al2O3 and AlON. The NMRspectra arecharacterized bythree distinctresonance peaksat114 , 66 and 12 , corresponding to 〔AlN4〕,〔AlO4〕and 〔AlO6〕respectively. The uantum chemistrycalculationsshowqd thatthe models with vacancieslocated at octahedralsitein B block are morestablethanthose with vacancieslocated attetrahedralsitein A blockforboth of γ Al2 O3 and AlON. In AlON, nitrogen atoms preferentially replace oxygen atoms in〔AlO4〕tetrahedrons, and the model with 〔AlN4〕is morestablethan that with 〔AlO4 xNx〕(x= 1 ,2 and 3) and 〔AlO6 - yNy〕(y= 1 ,2 ,3 and 4) , which isin agreement with theexperimental analysisby NMR.
关键词:
Al2 O3 and AlON
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