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1.
钢表面化学气相沉积TiC晶体的择优取向 总被引:1,自引:0,他引:1
本文用化学气相沉积(CVD)法,以TiCl_4-CH_4-H_2为原料气体,在不锈钢表面获得了致密的TiC膜.研究了TiC的成膜速度、表面形貌和晶体择优取向与沉积条什的关系.结果表明,沉积温度T_(dep),碳钛比CH_4/TiCl_4强烈地影响了TiC的成膜速度、表面形貌和晶体择优取向.CH_4/TiCl_4低时,TiC晶体的择优取向为(220):而CH_4/TiCl_4高时,TiC晶体的择优取向为(200).TiC晶体的择优取向主要取决于气氛中活性碳的平衡浓度。 相似文献
2.
Beta-type CVD-Si3 N4 plates (up to 1.1 mm thick) have been prepared by adding TiCl4 vapor to the system SiCl4 -NH3 -H2 at deposition temperatures of 1350° to 1450°C, while α-type or amorphous CVD-Si3 N4 was obtained without TiCl4 vapor at the same deposition temperature. Three to four wt % 777V was included in the β-type CVD-Si3 N4 matrix. The density, preferred orientation, and lattice parameters of β-type CVD-Si3 N4 were examined. 相似文献
3.
TOSHIO HIRAI KOICHI NIIHARA TAKASHI GOTO 《Journal of the American Ceramic Society》1980,63(7-8):419-424
A thermo gravimetric study of the oxidation behavior of chemically vapor-deposited amorphous and crystalline Si3 N4 (CVD Si3 N4 ) was made in dry oxygen (0.1 MPa) at 1550° to 1650°C. The specimens were prepared under various deposition conditions using a mixture of SiCl4 , NH3 , and H2 gases. The crystalline CVD Si3 N4 indicated a parabolic oxidation kinetics over the whole temperature range, whereas the amorphous CVD Si3 N4 changed from a parabolic to a linear law with increased temperature. The oxidation mechanism is discussed in terms of the activation energy for the oxidation and the microstructure of the formed oxide films. 相似文献
4.
KIJA LEE KAHO UEGAKI CHIHIRO NISHII TADASHI NAKAMURA AUSKA KUBOTA TSUNAO HIRAI KAZUTAKA YAMADA 《International Journal of Dairy Technology》2012,65(2):232-236
Computed tomography (CT) was performed on Gouda‐type cheese during ripening to evaluate gas hole formation and structural quality. The cheese was exposed to different ripening conditions, including variations in ripening temperature and concentration of butyric acid bacteria. Computed tomography images were obtained every 2 weeks for 16 weeks to assess the volume, shape and location of gas holes. The results demonstrate that CT makes the nondestructive monitoring of cheese gas hole formation and evaluation of the structural features of cheese possible throughout the ripening period. 相似文献
5.
唐新峰 《武汉理工大学学报(材料科学英文版)》2002,17(3)
1 IntroductionTheelectricaltransportproperties (conductiontype ,carrierconcentration ,carriermobility ,carriereffectivemass)andthethermaltransportproperties (atomdis placementparameter ,meanfreepathofphonon ,latticethermalconductivity)offilledskutteruditecomp… 相似文献
6.
K. HIRAGA M. HIRABAYASHI S. HAYASHI T. HIRAI 《Journal of the American Ceramic Society》1983,66(8):539-542
Microstructures of Si3 N4 -TiN composites prepared by chemical vapor deposition (CVD) were investigated by the multibeam imaging technique using a 1 MV electron microscope. High-resolution images showed a number of fibrous TIN crystallites dispersed in the matrix of CVD β-Si3 N4 . Crystallographic orientation relations between β-Si3 N4 and TiN were determined directly from the observed images in the subcell scale. The fibrous axis of TiN is parallel to the (110) direction of the NaCl structure and lies along the c axis of the hexagonal β-Si3 N4 crystal. Domain boundaries, planar faults, nonplanar faults, and dislocations were found in the CVD β-Si3 N4 matrix near the TiN crystallites. The origin of the structure defects is briefly discussed in connection with the formation of TiN crystallites in the matrix. 相似文献
7.
In this paper the chaotic phenomenon and bifurcation in numerical computation using the Runge-Kutta method to discretize the nonlinear differential equation are investigated. It is shown that the bifurcation condition in the discretized equation is given by the eigenvalue of the jacobian matrix of the original differential equation. As an example, the bifurcation and chaos when a second-order nonlinear equation is discretized by the Runge-Kutta method is investigated and it is shown that the scenario from a stable fixed point to chaos when the fourth-order Runge-Kutta method is applied is quite different from those of the second-order Runge-Kutta method 相似文献
8.
In this paper, bifurcation and the chaotic phenomenon in numerical computation are investigated using the generalized Euler method. In this method, the forward and backward Euler methods and the trapezoidal method can be represented as special cases. It will be made clear that, for some computation step size, the solution of the difference equation does not always approximate to the solution of the original differential equation; period-doubling bifurcations and the chaotic phenomenon occur in the solution of the difference equation. Two examples are shown to illustrate the effect of step size. 相似文献
9.
Investigation was made of the deposited rate,surface morphology and crystal pre-ferred orientation of the dense TiC coating onto austenitic stainless steel in relationwith CH_4/TiCl_4 mole ratio and temperature adopted in CVD processing. When theCH_4/TiCl_4 ratio is low or high,the preferred orientation may be(220)or(200),respec-tively,which is mainly dependent on the equilibrium concentration of active C in vapourphase. 相似文献
10.
A numerical calculation technique for computing bifurcation values of interconnected dynamical systems is presented. The technique is based on continuation methods in which the bifurcation value of interconnected dynamical systems can be calculated from the bifurcation value of a subsystem using a set of coupled differential equations. As an example, the value of the Hopf bifurcation of an interconnected dynamical system is calculated. 相似文献