泡沫Ni-32Cr合金的结构及其性能研究

以聚氨酯泡沫树脂为基体,采用浆料涂覆、电沉积、热解和合金化等技术制备出网状结构的高孔率泡沫Ni-32Cr合金.对该泡沫合金的形貌结构、成分分布和使用性能进行了分析研究.实验结果表明:该泡沫合金骨架平整,成分均匀,相对密度为6.4%,骨架的室温显微硬度HV为168,压缩强度约5MPa,且800℃时氧化1h,其增重率小于2×10-3.     

本底真空对磁控溅射镍铬合金薄膜电阻的影响

目的研究本底真空对溅射镍铬合金薄膜性能的影响。方法在不同溅射时间下制备了不同厚度的镍铬合金薄膜,采用4、6、8、10 h不同的抽真空时间制备薄膜样品,并在空气、氮气及真空气氛中,对同一工艺条件下制备的镍铬合金薄膜样品分别在300、400、500℃下进行热处理,所有样品分别测试方块电阻。结果不同厚度的镍铬合金薄膜的方块电阻与薄膜厚度之间存在非线性关系,样品的方块电阻随着溅射前抽真空时间的增加而降低。在真空和空气中进行热处理的薄膜的方块电阻变化规律一致,而在氮气中的则相反。结论本底真空残留气体对镍铬合金薄膜的氧化是引起薄膜电阻率增大的主要原因,即射频磁控溅射镍铬合金薄膜被氧化而使电阻率增大,随着溅射时间的增加,残留气体影响减小,导致电阻率降低。前期抽真空时间大于9 h,靶材溅射清洗时间大于110 min时,制备的镍铬合金薄膜电阻率才趋于稳定。     

连轧钢管机凹型槽轧辊的研制

本文选用镍铬钼合金球墨铸铁材质，凹型槽直接铸出工艺，试制连轧钢管机轧辊。在冲天炉熔炼条件下，炉前采用轻稀土镁复合球化、孕育处理工艺，球化等级达到了2—3级。各项性能指标达到了GB／T1504—91的要求，轧辊使用性能达到了国内知名厂家同类产品的先进水平。     

Ni－Cr衬底上MOCVD法制备YSZ过渡层的研究

用ＭＯＣＶＤ方法在柔性金属衬底上沉积超导膜是潜在的实用高温超导成材方法。用适当方法原位快速地制备有择优取向的防扩散过渡层是其中的关键。本文报导用有机源Ｙ（ｄｐｍ）_３和Ｚｒ（ｄｐｍ）_４，采用ＭＯＣＶＤ方法在Ｎｉ基合金衬底上沉积了Ｙ稳定的ＺｒＯ_２立方相过渡层，厚度约０．５μｍ。文中研究了氧分压和沉积温度对ＹＳＺ结晶和择优取向的影响。结果表明，在生长压力为１３０Ｐａ时，氧分压低至２０Ｐａ，制备出（１１１）取向为主的ＹＳＺ多晶膜，氧分压为５０～１００Ｐａ，则制备出（ｈ００）择优取向为主的ＹＳＺ膜。衬底温度太低，将导致ＹＳＺ膜质量变差。     

Ni-Cr合金在900～1000℃空气中的氧化

研究了两种不同Cr含量的熔炼Ni-Cr合金在900～1000℃空气中的氧化行为。1000℃时,合金氧化动力学遵循抛物线规律。Ni-20Cr合金1000℃氧化后生成了NiO／NiCr2O4／Cr2O3比较规则的复合氧化膜。在实验条件下,20％的Cr含量不足以使合金氧化后生成单一的Cr2O3外氧化膜。     

闪速炉废热锅炉水冷壁管的失效分析与对策

对闪速炉废热锅炉水冷壁管爆裂原因进行分析，确认爆裂是由低温硫酸露点腐蚀和烟气冲刷磨蚀引起。实践证明，等离子热喷涂及50Cr50Ni涂层能有效解决由此引起的爆裂失效问题。     

Effects of h-BN content on properties of Ni-Cr/h-BN composite

Ni-Cr/h-BN self-lubricating composities were prepared by powder metallurgy (P/M) method. The effects of hexagonal boron nitride (h-BN) content on the mechanical and tribological properties of the Ni-Cr/h-BN composites were investigated. The corresponding frictional models were established to analyze the formation of the lubricant h-BN films on the surfaces of the Ni-Cr/h-BN composites. The results show that, when the content of h-BN increases from 5% to 15% (mass fraction), the bending strength of the Ni-Cr/h-BN composite decreases from 96.670 MPa to 17.319 MPa, and the hardness (HB) decreases from 33 to 14. The friction coefficient of the Ni-Cr/h-BN composite decreases firstly from 0.385 to 0.216, and then increases to 0.284, while the wear rate decreases firstly from 4.14×10⁻⁹ kg/(N·m) to 1.35×10⁻⁹ kg/(N·m), then increases to 2.36×10⁻⁹ kg/(N·m). The best comprehensive mechanical and tribological properties can be obtained between 10% and 12% h-BN addition.     

Hot-corrosion mechanism of Ni-Cr coatings at 650 ℃ under different simulated corrosion conditions

The oxidation and lower temperature hot corrosion (LTHC) processes occurring on the surface of Ni-Cr coatings pro-duced by high velocity arc spray (HVAS) were studied. Several different conditions were studied under simulated boiler conditions at 650 ℃. The protection effect of an A1 coating deposited by HVAS onto the Ni-Cr coating was also investigated. Microscope,X-ray diffraction and corrosion rate curves have been used to analyze corrosion mechanisms. The experimental results show that: 1)The oxidation rates are almost superposed in both air (no SO3) and in simulated coal-fired gas (containing SO<,3>) as long as no salt was present on the surface. These rate curves show a logarithmic relationship. 2) When the surface is coated with salt (75%K2SO3 25%Na2SO3) the rate curve for LTHC of the Ni-Cr coated surface shows a parabolic shape in the simulated coal-fire flue gas. In air only the oxidation reaction takes place, the second type of LTHC was not seen. And 3) the AI over coating on the Ni-Cr enhances resistance to LTHC because an inter-metallic compound, Al<,3>Ni<,2>, forms at the Al/Ni-Cr interface and because of the increase in coating thickness.     

一种Ni-Cr@Al/CuO钝感含能元件的制备及性能

为了提高Ni-Cr薄膜发火件的安全性和点火能力,使用磁控溅射技术将Al/CuO含能薄膜与Ni-Cr薄膜发火件复合,制备了一种新型的Ni-Cr@Al/CuO钝感含能元件。该Ni-Cr@Al/CuO钝感含能元件既可以用作换能元,又可以作为最简单的电点火元件,从而简化点传火序列,适应弹药微型化的发展需求。测试其1A1W5min安全性、电发火感度和点火能力。结果表明,Ni-Cr@Al/CuO钝感含能元件满足1A1W5min安全性要求;50 ms临界发火电流为3.08 A,最小全发火电流为3.18 A,最大不发火电流为2.98 A,安全裕度较高;在相同条件下,Ni-Cr@Al/CuO钝感含能元件可以点燃硼/硝酸钾,并且可实现1 mm的间隙点火,而Ni-Cr薄膜发火件不能成功点燃硼/硝酸钾。     

Corrosion of nickel-chromium alloys, stainless steel and niobium at supercritical water oxidation conditions

Results of immersion tests of UNS N06625 (alloy 625), UNS S31609 (alloy 316 L), Ni-20Cr alloy and Nb coupons exposed to oxygenated ammoniacal sulphate solution at supercritical water oxidation (SCWO) conditions are presented. The corrosion behavior of the alloy 316 L (UNS S31603) SCWO reactor tubing is also presented under the same conditions. Immersion coupons corroded at a rate not exceeding 40 mm yr⁻¹ while the reactor tube itself corroded at a rate of between 160-1500 mm yr⁻¹, depending on which length of the reactor is considered to have corroded. Morphological and chemical analysis of the oxides present on the coupon samples suggest that iron oxides, which had initially precipitated on the corroding alloy 316 tube surface, were removed by heat flux-driven fluid mechanical action and transported through the reactor where they deposited on the coupons. Niobium was resistant to corrosion at the tested conditions.