C.H. Surberg
,
P. Stratton
金属学报(英文版)
Although cold treatments have been used to reduce the retained austenite in the cases of carburised steels for many years, there are little data on deep cold temperatures below -70oC or treatment times longer than an hour or two. This study set out to determine the effects of such deep cold treatments at temperatures down to -150oC for up to 24 hours. The study investigated the effects of deep cold on microstructure, hardness profile, residual stress and internal oxidation on two typical carburising steels, 16MnCr5 and 21NiCrMo2.
The study found that for both 16MnCr5 and 21NiCrMo2 carburised to a case depth of approximately 0.8mm, the longer and colder the deep cold treatment, the more of the austenite retained in the case was converted to martensite and the harder it became. After low temperature tempering the hardness difference was smaller, but still significant. In both steels the case appeared more refined and homogeneous after deep cold treatment. Deep cold treatment had a negligible effect on the core properties of either steel.
关键词:
Carburised steel
,
steel
,
Deep
,
cold
,
Retained
,
aus
Journal of Physics D-Applied Physics
Magnetic, electronic transport and magneto-transport behaviours of (Co1-xMnx)(2)P (0.55 <= x <= 0.675) compounds have been systematically investigated. A typical metallic-conductivity behaviour is observed in the ferromagnetic compound (Co0.45Mn0.55)(2)P. The increase in the Mn concentration gives rise to dramatic changes in magnetic, electronic transport and magneto-transport behaviours. With increasing temperature, a first-order phase transition from antiferromagnetism to ferromagnetism takes place at about 145 K, 185K and 240K for x = 0.60, 0.625 and 0.65, respectively. (Co0.4Mn0.6)(2)P and (Co0.375Mn0.625)(2)P compounds experience a metal-insulator transition (Anderson transition) with decreasing temperature. An external magnetic field of 5 T strongly influences the Anderson transition, lowering the transition temperature from 80 to 55K for (Co0.4Mn0.6)(2)P and from 115 to 70K for (Co0.375Mn0.625)(2)P. In contrast with this metal-insulator transition, an insulating behaviour appears in the temperature range from 10 to 300K for (Co0.35Mn0.65)(2)P and (Co0.325Mn0.675)(2)P compounds. Below the antiferromagnetic-ferromagnetic transition temperature TAF-F, a metamagnetic transition can be induced by an external magnetic field. The metamagnetic transition is accompanied by a maximum magnetoresistance ratio of -7%, -6.3% or -3.7% at 5 T in the (Co0.4Mn0.6)(2)P, (Co0.375Mn0.625)(2)P or (Co0.35Mn0.65)(2)P compound at 10 K. The mechanisms of magnetoresistive behaviours are discussed in terms of the formation of a super-zone gap in the antiferromagnetic state.
关键词:
metamagnetic-transition;solid solutions;resistivity;systems;magnetoresistance;anomalies;alloys;field
钱建刚
,
滕晓明
,
刘玉芬
,
黄巍
稀有金属材料与工程
利用金相显微镜(OM)、扫描电子显微镜(SEM)及能谱(EDS)等分析测试手段,研究AZ91D镁合金上直接化学电镀Ni-P的沉积过程.结果表明:活化后的表面上不同位置处最初沉积Ni的过程不同.在活化后的块状物上,由于氟化物的溶解,Mg置换出Ni,因此最初"块状物"上只有Ni沉积,没有P.β相和α相边缘则是由于其电位较高,附近的Ni2+得到Mg失去少量电子后还原沉积出高催化活性的Ni核,催化了次亚磷酸钠还原沉积出P和Ni.
关键词:
AZ11D镁合金
,
Ni-P镀层
,
沉积
钟惠妹
,
黄振霞
,
许彩霞
,
陈震
电镀与涂饰
doi:10.3969/j.issn.1004-227X.2005.06.003
在有机高分子聚合物薄膜,如投影仪专用胶片上超声波化学镀Ni-Cu-P合金,研究了镀液各组分浓度、pH值变化对沉积速度的影响.通过扫描电镜(SEM)观测镀层的表面形态及厚度,并用其所附带的能谱(EDS)分析镀层成分,采用透射电镜(TEM)观测镀层中粒子的微观形貌及大小,利用X-射线衍射(XRD)表征镀层的微观结构.结果表明,Ni-Cu-P合金化学镀层为非晶态合金,光亮、均匀,与基体结合面平整.镀层厚度100 μm,镀层颗粒大小在30～40 nm,各成分含量分别为77.73%～90.64% Ni,0.38%～5.27% Cu,7.23%～14.30% P.
关键词:
超声波
,
化学镀
,
Ni-Cu-P合金镀层
,
沉积速度
王雪俊
,
夏海平
材料导报
制备了χNb2O5-(10-χ)La2O3-60P2O5-10Na2O-19BaO-Eu2O3(以mol%记χ=9、7、5)的玻璃,测定了玻璃的吸收光谱、发射光谱、激发光谱、声子边带谱和差热分析曲线.从发射光谱出发获得了Eu3+光学跃迁的J-O参数Ω2、Ω4,并计算了Eu3+离子5DO→7FJ(J=1,2,4)的自发辐射跃迁几率A以及受激发射截面σp.结果显示,随着La2O3的增加和Nb2O5的减少,玻璃样品的热稳定性降低,强度参数Ω2减小,表明材料的对称性提高,共价性减弱,Eu-O键强减弱;随着La2O3的增加,电-声子偶合减弱,受激发射截面σp减小.
关键词:
光学材料
,
Eu3+离子掺杂铌镧玻璃
,
光谱性质
,
J-O理论
,
强度参数
,
受激发射截面
Materials Letters
The effects of P and B on the creep behavior of 718 alloys are discussed in this paper. The result implies that P and B have little effect on the gamma" and gamma' phases of the alloy, but they can enhance the grain boundary strength by segregating there, which can be of beneficial to the higher creep properties. P also may increase the grains strength through solid solution. The beneficial effect of P and B were presented in both standard IN718 alloy and DA718 alloy. Adding P and B together does a better work than adding P alone. (c) 2006 Elsevier B.V. All rights reserved.
关键词:
P and B;718 alloy;creep;grain boundaries;heat treatment;stress rupture;phosphorus;superalloy;boron
宿辉
,
蔡伟
,
曹茂盛
材料科学与工艺
doi:10.3969/j.issn.1005-0299.2008.03.004
为解决Ni-P-(SiC)P镀层中基体的金属键与增强体的共价键间相容性差,增强体颗粒易脱落,镀层性能降低等问题.采用简单的化学镀方法实现了(SiC)P表面修饰、改性,得到了涂覆型改性(Ni/SiC)P,以(Ni/SiC)P为第二相粒子制备了Ni-P-(Ni/SiC)P化学复合镀层,并初步分析了复合镀机理.实验结果表明:温度、pH值、搅拌速率及(Ni/SiC)P加入量对Ni-P-(Ni/SiC)P镀层的沉积速率及沉积量有较大的影响,本实验条件下的最佳温度为82～86℃;最佳pH值为4.2～4.6;最佳搅拌速率为200 r/mim;最佳粒子加入量10 g/L.SEM、EDS分析显示Ni-P-(Ni/SiC)P镀层均匀、致密,Ni、P、Si沉积量大,耐磨性实验证明Ni-P-(Ni/SiC)P化学复合镀层硬度、耐磨性优干常见的Ni-P、Ni-P-(SiC)P镀层.经表面修饰、改性后得到的(Ni/SiC)P可以进一步提高Ni-P-(SiC)P镀层的使用性能.
关键词:
化学镀
,
(Ni/SiC)P
,
镀层
,
工艺条件
,
耐磨性
宿辉
,
蔡伟
,
曹茂盛
材料工程
doi:10.3969/j.issn.1001-4381.2007.10.010
为解决裸(SiC)p在实际应用中存在的不足,采用简单的化学镀方法对其表面进行改性,得到了包覆型的改性(Ni/SiC)p,以(Ni/SiC)p为第二相粒子制备了Ni-P-(Ni/SiC)p化学复合镀层,经扫描电镜、能量散射仪、硬度等测试,并与常见的Ni-P化学镀层、Ni-P-(SiC)p化学复合镀层比较,结果显示:Ni-P-(Ni/SiC)p镀层具有组成均匀、硬度高、镀层耐磨损等优点,为(SiC)p增强金属镀层及基体材料的研究提供了一个新的思路.
关键词:
化学镀
,
(Ni/SiC)p
,
镀层
,
硬度
