WANG Lu, WANG Fu-chi, LIU Guo-quan, FAN Qun-bo. Numerical Simulation on Melting and Flattening Process of Metal and Ceramic Powders in Plasma Spray[J]. Journal of Materials Engineering, 2000, 0(12): 3-5.
In this paper, the melting and flattening process of metal and ceramic powders in plasma spray are studied numerically. The method of determining the spraying distance for forming good coatings and the numerical results describing the flattening of droplets (metal and ceramic) impacting onto the substrate (smooth and rough surface) are obtained.Problems of these types are of broad general importance in functionally gradient materials and plasma spraying.
NIU Jian-ping, SUN Xiao-feng, JIN Tao, YU Yang, YANG Ke-nu, GUAN Heng-rong, HU Zhuang-qi. The Influence on Denitrogenation During Refining Ni-Base Superalloy by Using CaO Crucible[J]. Journal of Materials Engineering, 2000, 0(12): 6-7,11.
The changing law of N element during the process of VIM refining Ni-base superalloy by using CaO crucible and the influence of aluminium to denitrogenation are studied.The influence factors and principles on denitrogenation are preliminary discussed.
ZHANG Shao-bo, FU Hui-min, ZHANG Ying-fu. Unified Stress-Rupture equation[J]. Journal of Materials Engineering, 2000, 0(12): 8-11.
A unified stress-rupture equation and a unified equation are given in this paper. The equation can compound the L-M equation, G-D equation, M-S equation and M-H equation into a unified form, furthermore, it can express the relation among the stress-rupture limit, stress and temperature exactly which cannot be expressed by those four equations. Contrasted with those four stress-rupture equations given in the standard,this unified equation has the advantages of high precision and wide applicability.
JIAO Huan, ZHOU Wan-cheng, LI Xiang. Growth Rate and Deposition Process of SiC with Water Vapor Introduced by CVD[J]. Journal of Materials Engineering, 2000, 0(12): 12-14,18.
The growth rate and deposition process of polycrystalline silicon carbide by chemical vapor deposition(CVD) with the introduction of water vapor were investigated. The water vapor were introduced into reactor using Ar as the carrier gas at 20~80℃. Comparing of growth rate and oxygen content was made between the process with water vapor and without water vapor. The results show that the growth rate is considerably influenced by the introduction of water vapor, which is assumed to change the reaction path.
LÜ Jun, ZHENG Zhi-Xiang, JIN Zhi-hao, WANG Yong-Lan. Thermal Shock Resistance for Wisker and Particle Toughing Al2O3 Ceramic Matrix Composites[J]. Journal of Materials Engineering, 2000, 0(12): 15-18.
The thermal shock resistance of the Al2O3-SiCw and Al2O3-TiCp ceramic matrix composites were measured by the quenching test. And the fracture surface of two materials were observed by SEM.The main reasion of the improving thermal-shock resistance was also reseached.The results show that Both materials exhibited better thermal shock resistance than matrix.The Al2O3-SiCw composite, however, displayed better damage tolerance and higher thermal shock resistance.From SEM observation and theoretical analysis,it was inferred that this phenomena can be attributed mainly to the microstructure and the toughing mechanism of the materials.
YU Jia-Guo, ZHAO Xiu-Jian, HAN Jian-jun, ZHAO Qing-Nan. Mechanism Studies on Grain Growth of the Sol-gel Derived TiO2 Nanometer Thin Films[J]. Journal of Materials Engineering, 2000, 0(12): 19-21,25.
The uniform, transparent anatase TiO2 nanometer thin films were prepared via the sol-gel method on soda-lime glass. The grain size and transmittance were characterized by transmission electron morphology (TEM), X-ray diffraction (XRD) and UV-visible spectrophotometer (UV-VIS) etc. The results show that with increasing of coating cycle times and heat-treatment time, the average grain size almost linearly increase. However, only increasing the heat-treatment time, the average grain size and absorption edge wavelength of TiO2 films has no obvious change. Therefore, the mechanism of grain growth in TiO2 thin film is probably as follows: the grain of coating last time will become grain core of coating next time, TiO2 sol constantly deposited on the surface of TiO2 grain and formed membrane with increasing of coating cycle times. Finally, TiO2 grain in the films steadily grew.
LIU Qi-cheng, LIU Pei-ying, TAO Ye, LIU Li. Investigation on TiN Coating by CVD and Pulsed D. C. PCVD methods[J]. Journal of Materials Engineering, 2000, 0(12): 22-25.
A pulsed D.C plasma chemical vapor deposition in industrial set-up for deposition of TiN coatings on cemented carbide SC30 was performed. The microstructure and performance of TiN coatings by CVD and pulsed D.C.PCVD methods were investigated. Microstructure of coatings was studied by SEM and XRD. It was found that the microstructure of PCVD TiN coatings was much finer and regular in shape than that of CVD coatings. The morphology of the PCVD coating is with fine and spherical grain shape,while the grain of CVD coating was polygonal. The toughness and adhesion of the coatings were examined by the indentation method. It was shown that the toughness and adherence of PCVD TiN coating were better than that of CVD coatings.
ZHANG Hai-quan, ZHANG Yan-hua, ZHANG Xing-an, ZHANG Tian-cang, SUN Cheng-bin. Effect of Heat Treatment on the Impact Toughness in Inertia Friction Welded Joints[J]. Journal of Materials Engineering, 2000, 0(12): 26-28.
The effect of post-weld heat treatment on the impact toughness in inertia friction welded joints of carbon steel was studied in this paper. The result show that the post-weld heat treatment greatly affected the impact toughness of inertia friction welded joints. The impact toughness of the welded joints can be improved by an adequate post-weld heat treatment.
JI Yuan, ZHONG Tao-xing, GAO Xia-xia, SHI Ning, CUI Yan. Scanning Thermal Probing of Interfacial Thermal Conductivity of Metal Matrix Composites[J]. Journal of Materials Engineering, 2000, 0(12): 29-31,41.
Interfacial features and interfacial thermal conductivity of three kinds of metal matrix composites (MMC) have been comparatively studied by the scanning thermal probing with the micro-sized special resolution. The statistical method was used to process and translate topographic and thermal voltage data of scamming thermal microscopy (SThM). The data of interfacial width and interfacial thermal conductivity were obtained. The results reveal that the macro thermal conductivity of the MMC can be critically dependent on the reinforcing-matrix interfacial thermal conductivity.
LUO Wei. Thermal Shock Behavior of Al2O3/TiO2-NiCrBSi Graded Thermal Barrier Coatings Produced by Flame Spraying[J]. Journal of Materials Engineering, 2000, 0(12): 32-34,38.
The failure behaviors of Al2O3/TiO2-NiCrBSi graded thermal barrier coatings produced by oxy-acetylene spraying under the condition of thermal shock with water quenching have been studied. The results show that the thermal shock resistance of the coatings increases with decreasing in component gap between layers. The failure is caused by the cracks both in layers and in the interface between layers. For the coating with better component gradient,its failure is attributed to propagating of the cracks which are in layers, leading to the formation of network cracks. For the coating with bigger component gap between layers,its failure is attributed to the rapidly propagation of the cracks which are in the interface between layers, leading to the coating peel off the substrate. In the case of moderate gap the coating′s failure is due to the propagation of both the cracks, leading to the failure of the coating in the form of localized fracture.
FU Gao-sheng, QIAN Kuang-wu, CHEN Wen-zhe, KANG Ji-xing. Analyses of the Current Situation and Existing Problem in the Research of Aluminum Sheet Used for Making Can[J]. Journal of Materials Engineering, 2000, 0(12): 35-38.
The present situation of internal and external research and development,and existing problems of aluminum sheet used for making easy open-end can or pressure can are discussed and analyzed. The key technology and main settlement way of making internal material used in pressure can are pointed out.
LI Shi-bo, ZHANG Li-tong. A New High Temperature Material Si(B)CN[J]. Journal of Materials Engineering, 2000, 0(12): 39-41.
Amorphous silicon carbonitride (SiCN) and boron-containing silicon carbonitride (SiBCN) have better high temperature properties than silicon carbide (SiC) and silicon nitride (Si3N4). The glass transition temperature (Tg) of SiCN is above 1400℃,and start to decompose to polycrystalline of SiC and Si3N4. The SiBCN material remains amorphous at temperature up to 1700℃ and begin to crystallize above 1800℃. SiCN and SiBCN have an excellent resistance to oxidation at 1600℃. According to the needs of high temperature materials, we discuss the thermal stability, oxidation resistance, and resistance to creep of those materials, respectively. Prospect the development of SiCN and SiBCN as high temperature ceramic materials.
CUI Bin, GAO Feng, QU Shao-bo, YANG Zu-pei, TIAN Chang-sheng. Development of Preparation Techniques of Lead based Relaxor Ferroelectric Ceramics[J]. Journal of Materials Engineering, 2000, 0(12): 42-46.
This paper briefly introduces the development in preparation techniques of lead-based relaxor ferroelectric ceramics. Some new preparation techniques, which emerges recently, such as mechanochemical processes, low-temperature combustion systhesis, solution coating technique, microemulsion processes, and modified mixed-oxide method are reviewed.
