材料期刊网

DEPOSITION OF c-BN FILMS AND ADHESION IMPROVEMENT

S.R. Lee , E.S.Byon and Y.-W. Seo 1)Korea Institnte of Machinery and Materials , Changwon 641-010 , Korea 2)V & P International Co. , Ltd , 705-9 , Gozandong , Inchon 405-310 , Korea Manuscript received 26 August 1996)

金属学报(英文版)

Cubic boron nitride (c-BN) films were successfully grown on Si(100)substrates by a helicon wave plasma-assisted chemical vapor deposition technique.The lower limits of rf substrated bias voltage and plasma density for formation of a single phase c-BN film were 350V and 4.5×10~(10) cm~(3),respectively. The grown c-BN films demonstrated a poor adhesion to the substrates. A postannealing treatment at 800℃ C in N_2 atmosphere was found very effective in relieving the compressive stress in the films which were thereby stabilized to improve the adhesion.

关键词: :cubic boron nitride , null , null , null

A MODEL FOR NUMERICAL CALCULATION OF UNSTEADY TEMPERATURE FIELD

S. X. Wang , D. S. Zheng and Y. L. Liu 1) Department of Material Engineering , Luoyang Institute of Technology , Luoyang 471039 , China 2) Luoyang Copper (Group) Co. , Ltd , Luoyang , China

金属学报(英文版)

The model established in this paper for calculating the unsteady temperature field, in which physical parameters varies with temperatures, is simplified as compared with the classical one by defining the heat conductivity as function of temperature and dealing with the latent heat of phase transformation and boundary conditions. The results show that the probability of absolute error less 2℃ between the calculated and measured values in temperature field calculation reaches above 80%.

关键词: temperature field , null , null

MEASUREMENT AND APPLICATION OF PHYSICAL PARAMETERS IN UNSTEADY HEAT CONDUCTION

S. X. Wanng , D. S. Zheng , Y. L. Liu 1) Department of Material Engineering , Luoyang Institute of Technology , Luoyang 471039 , China 2) Luoyang Copper (Group) Co. , Ltd , Luoyang , China

金属学报(英文版)

As far as the accuracy of calculating unsteady temperature field is concerned, it is very important to find the accurate physical parameters such as specific heat, thermal conductivity, latent heat of phase transformation and surface heat flux. The model for calculating H and Q is established in this paper. The measurement methods and data processing for physical parameters such as volume specific heat C, thermal conductivity k, volume latent heat of phase transformation c1 and surface heat flux are introduced The physical parameters of 1Cr18Ni9Ti and 45 steels and the surface heat flux for 1 Cr18Ni9Ti probe cooled in water,10% NaCl water and oil with different temperatures are measured, respectively. These data show that the probability of absolute error less than 2* C between the calculated and measured values in temperature field calculation reaches above 80% if using the above physical parameters, which provides a reliable technology basis for precise calculation of temperature field.

关键词: unsteady temperature field , null

The frequency dependence of the effective dielectric function of composites with periodic geometry

Solid State Communications

By using an analytic expression of the effective dielectric function of the composite with a periodic geometry which we have derived by using the Fourier expansion technique, we calculated and discussed the frequency dependence of the effective dielectric function, and compared it with those prospected by the scale theory. Copyright (C) 1996 Published by Elsevier Science Ltd

关键词: dielectric response;conductivity;constant;lattices;spheres

Calculation of the electrical field in the periodic composite and evaluation of the nonlinear susceptibility of the periodic composite

Solid State Communications

A simple Fourier approach to the calculation of the space dependent electrical field in periodic composite was present. A series expression of the field was obtained. By using this expression, the frequency-dependent cubic nonlinear susceptibility of metal-insulator composite with periodic structure was studied. (C) 1997 Elsevier Science Ltd.

关键词: dielectric response;effective dielectric-constant;inhomogeneous-media;approximation;bounds

Introduction to atmospheric corrosion research in China

Science and Technology of Advanced Materials

In this paper, we introduce the research on atmospheric corrosion in China. We describe the climate characteristics and the classification of atmospheric corrosivity across the whole country. We also describe the rusting evolution under simulated wet/dry cyclic conditions. (C) 2007 NIMS and Elsevier Ltd. All rights reserved.

关键词: atmospheric corrosion;corrosivity;rusting evolution;weathering steels;rust;mechanism;so2;o-3;no2

Effect of pressure on thermal stability of Mg65Cu25Y10 bulk metallic glass

Scripta Materialia

The pressure effect on thermal stability of Mg65Cu2Y10 bulk metallic glass has been investigated in the pressure range up to 4 GPa. It was found that the behavior of the onset crystallization temperature versus pressure significantly differs in various pressure ranges. (C) 2003 Published by Elsevier Ltd. on behalf of Acta Materialia Inc.

关键词: metallic glass;stability;phase transformation;pressure;amorphous-alloys;crystallization;nanocrystallization;transition;liquid;phase

In situ observation of pit initiation of passivated AZ91 magnesium alloy

Corrosion Science

The initiation and growth process of pit on passivated AZ91 magnesium alloy in an atmosphere of water vapor was studied using an environmental scanning electron microscope (ESEM). The results showed that pitting corrosion only occurred at the place with the segregation of salt particles. The mechanism for pit initiation was discussed. (C) 2008 Elsevier Ltd. All rights reserved.

关键词: Magnesium;wet-dry conditions;pitting corrosion;stainless-steel;localized;corrosion;charged magnesium;chloride solution;micro-droplets;al-alloys;secm;mechanism

Strengthening and improvement of sulfide stress cracking resistance in acicular ferrite pipeline steels by nano-sized carbonitrides

Scripta Materialia

Methods used to strengthen pipeline steels generally involve a reduction in their sulfide stress cracking (SSC) resistance. A non-quench ageing process is proposed to provide higher strength combined with more excellent SSC resistance for acicular ferrite (AF) pipeline steels, while microstructural characteristics are retained. (C) 2005 Acta Materiala Inc. Published by Elsevier Ltd. All rights reserved.

关键词: ageing;strengthening;sulfide stress cracking;pipeline steels

Hardness and strain rate sensitivity of nanocrystalline Cu

Scripta Materialia

The measured hardness of nanocrystalline Cu with grain sizes (( as small as 10 nm still follows the Hall-Petch relation. A rate sensitivity of 0.06 +/- 0.01 and a flow stress activation volume of 8b(3) were determined at d = 10 nm, suggesting grain boundary activities are enhanced but not yet dominant in the plastic deformation. (c) 2006 Published by Elsevier Ltd. on behalf of Acta Materialia Inc.

关键词: nanocrystalline Cu;hall-petch relation;grain size;strain rate;sensitivity;plastic-deformation;activation volume;tensile behavior;copper;metals;strength;ductility;fcc;ni;temperature