导磁体在汽车零件感应加热中的应用技术

本文简单介绍了导磁体工作的基本原理，并给出在汽车零件大规模生产中所积累的导磁体应用的一些经验，以阐明如何更有效地使用导磁体。     

Degradability and biocompatibility of bioglass/poly(amino acid) composites with different surface bioactivity as bone repair materials

Bioglass (BG) possesses excellent bioactivity and has been widely used in the manufacture of biomaterials. In this study, a composite with different surface bioactivity was fabricated via in situ melting polymerization by incorporating BG and poly(amino acid) (PAA) at a suitable ratio. The structure of the composite was characterized by Fourier transform infrared spectroscopy and XRD. The compressive strength of the BG/PAA composites was 139 MPa (BG:PAA = 30:70). The BG/PAA composites were degradable, and higher BG in composite showed higher weight loss after 4 weeks of incubation in simulated body fluid. In addition, the BG/PAA composite maintained adequate residual compressive strength during the degradation period. The SEM results showed the differences in surface bioactivities of the composites directly, and 30BG/PAA composite showed thicker apatite layer and higher Ca/p than 15BG/PAA. in vitro MG-63 cell culture experiments showed that the composite was noncytotoxic and thus allows cells to adhere, proliferate, and differentiate. This indicates that the composite has good biocompatibility. The implantations in the bone defects of rabbits for 4 and 12 weeks were studied. The composites had good biocompatibility and were capable of guiding new bone formation without causing any inflammation. The composite may be successfully used in the development of bone implants.     

Oxidation Performance of Fe-Al/WC Composite Coatings Produced by High Velocity Arc Sprayed at 650 ℃

Fe-Al intermetallics with remarkable high-temperatureintensity and excellent erosion,high-temperatureoxidation and sulfuration resistance are potential lowcost high-temperature structural material.ProducingFe-Al/WC composite coating by high velocity arcspraying(HVAS)on structural materials would notonly obviate the problems faced in fabrication of thesealloys into useful shapes,but also allow the effectiveuse of their outstanding high-temperature performance,which might thus promisingly mak…     

金属材料屈服强度的应变率效应和热激活理论

对４种金属材料进行了应变率为１０＾－４－１０＾３ｓ＾－１的拉伸试验，结果表明，屈服中度随应变率的升高分两阶段线性升高，提出了位错线热振动对加载频率的响应的热激活作用机理，依据该机理计算所得Ⅰ，Ⅱ区临界应变εｃ与实测值相符，并在此基础上将应变率对掘强度影响的机制图重新划分为：Ｉ区，富热激活区；Ⅱ区，贫热激活区。     

数控机床的可靠性分析

从不同侧面分析了数控机床的可靠性,阐述了提高数控机床可靠性的方法。     

自硬型芯工艺在异型铸件生产中的应用

针对异型铸件(指有狭窄缝隙、结构形状特殊、难于用常规水玻璃涂料工艺进行结壳),介绍了灌浆式自硬型芯的制作过程,提示了模具开设的要点,着重分析了浇注、补缩系统的设置等精密铸造工艺的要素,使自硬型芯工艺成功地在较大异型精铸件生产上得到应用。     

微量Ge对大气下液态Sn抗氧化性能的影响

采用观察液态Sn表面氧化行为和刮取表面氧化渣的方法,研究了微量元素Ge对液态Sn在大气和250℃条件下表面抗氧化性能的影响,并与纯Sn的氧化行为进行对比;利用X射线光电子能谱仪(XPS)、扫描电子显微镜(SEM)研究了合金表面元素的含量、价态,及合金氧化后的表面形貌.结果表明:当微量元素Ge浓度达到0.01%时(质量分数),大气下液态Sn表面具有很好的抗氧化性能,同时微量元素在液态Sn表面高度富集.XPS分析表明:表面富集的Ge以4价氧化物形式存在.静态液面氧化时,Ge在液态Sn中迅速偏析,并形成一种保护性的致密氧化膜,是提高液态Sn抗氧化性能的原因.