新型纳米分散剂提高醇基涂料悬浮稳定性的研究

对用新型纳米分散剂提高醇基涂料悬浮稳定性进行了研究 ,试验结果表明 ,只有新型纳米分散剂和有机助剂配合使用 ,才可取得明显的悬浮效果 ,醇基涂料的 2h、 2 4h、 48h和 72h悬浮率分别达到 99%、 98%、 96 %和 94%。这种醇基涂料还具有强度高、发气量低、涂刷性好和点火不起泡等特点。     

海泡石醇基涂料悬浮剂的制备与应用研究

以海泡石作为悬浮剂制备醇基涂料，通过研究海泡石和涂料其他各组分加入量对涂料主要性能的影响和变化规律，得出涂料的最优配方。结果表明：加入量海泡石为7%，酚醛树脂为2%,PVB为0.75%，硅溶胶为4%时，制备的醇基涂料悬浮性、涂刷指数、高温抗裂性最佳，发气量、涂层耐磨度符合相关行业标准。     

辽宁省建平县富山石粉厂——铸造用醇基涂料悬浮剂-锂基膨润土 ：水基涂料增稠防沉剂-钠基膨润土

锂基膨润土在醇基溶液中有高度分散性、粘稠性、流变性、触变性及很强的悬浮性，能有效地将溶液中其它耐火材料分散并悬浮起来，防止溶质沉淀及分层。是生产铸造醇基涂料的优质悬浮剂。采用锂基膨润土为悬浮剂配制的醇基快干涂料，具有不沉淀、分散性高，快干、强度高，无污染，铸件表面光洁度高的特点。     

铸钢用醇基粉状涂料的研制

重点研究了悬浮剂聚乙烯醇缩丁醛（ＰＶＢ）与消泡剂和辅助悬浮剂各种膨润土对醇基粉状铸钢涂料的影响，分析了球磨与棒磨研磨涂料的特点，确定了醇基粉状铸钢涂料的配制工艺。生产实践表明，研制的醇基粉状铸钢涂料运输和贮存方便、安全，贮存期长，稀释搅拌容易，涂料的悬浮性、触变性、流平性能好，抗粘砂能力强，涂层烧结壳易剥离，铸件表面光洁     

镁橄榄石粉醇基粉状涂料的研制

介绍了镁橄榄石粉醇基粉状涂料的原材料选择、配方、研磨工艺、稀释方法、涂料性能和生产应用效果等。醇基粉状涂料研制的关键是保证悬浮稳定性，本涂料应用了一种自配的高效复合悬浮列，悬浮率２ｈ可达到９８％左右，可与醇基液体涂料相媲美。     

铸铁用醇基涂料的配制

１醇基涂料的组成铸造用涂料应具有优良的工作性能和工艺性能，这些性能主要是通过合理的配方和正确的制备工艺获得的。涂料主要由耐火粉料、粘结剂、悬浮剂、载液和附加物组成。１．１耐火粉料涂料用耐火材料根据铸造合金的种类确定。一般铸铁用涂料的耐火材料有石墨粉、锆石粉、棕刚玉、铝钒土、滑石粉等，它们的性质如表１所示。耐火粉料由耐火材料破碎研磨而成。耐火粉料粒度和密度是影响涂料悬浮性的重要因素。耐火粉料在涂料中悬浮的条件为：式中Ｒ－耐火材料的颗粒半径；涂料的静切力限；固－耐火材料的密度；液－载波密度。由上式可…     

新型环保醇基铸造涂料悬浮剂研究

通过对SN悬浮剂、BTA悬浮剂、二元悬浮剂的悬浮性试验，找到了可替代有机膨润土的新型醇基铸造涂料悬浮剂——二元悬浮剂。试验结果表明，该悬浮剂在性价比、环保方面完全可与有机膨润土相比，能够适应21世纪绿色铸造的要求。     

镁合金金属型铸造涂料及制备方法

提供一种镁合金金属型铸造涂料及制备方法，其化学组分质量百分比为：滑石粉3～8％、硅藻士2～5％、粘结剂1．5～49／6、悬浮剂0．3～2％、阻燃剂2～7％和水75～90％。粘结剂可以为水玻璃、硅溶胶或磷酸铝，悬浮剂可以为凹凸棒粘土、坡缕石粘土等，阻燃剂可以为NH4BF4、KBF4、烷基磺酸钠和硼酸等。本发明制备的镁合金金属型铸造涂料，具有较强的保温性、阻燃性、粘结性和涂覆性，并且具有优良的悬浮性，     

涂料对轴承座铸件内表面废品率的影响

1铸件技术要求轴承座是微型汽车传动轴与后桥连接处的连接件，重9kg，灰铸铁，铸造采用合脂油芯，装配后内部有几个传动的伞齿轮及差速器等零件。由于这些齿轮的磨损会直接影响到汽车的性能，轴承座内腔清洁度要求很高．内表面不允许有粘砂、夹渣、砂孔和气孔等，因此，型芯徐（浸）涂料是生产中必不可少的一道工序。2涂料对铸件质量的影响2．1涂料涂覆工艺对废品率的影响GM牌醇基涂料为例，各种涂覆工艺对内表面废品率的影响如表1所示。由表1可知，涂料对铸件内表面废品率的影响是相当明显的。同时，涂覆工艺不同，铸件内腔表面质量不合格…     

锂基膨润土的制备及其在铸造涂料中的应用

概述了锂基膨润土的制备过程。通过X射线衍射、差热分析及热失重分析,对钙基膨润土和锂基膨润土的矿物结构和失水特征进行了分析,并测试了膨润土的悬浮度;同时介绍了采用锂基膨润土作悬浮剂所制铸造涂料的配制工艺、性能和使用效果。结果表明,制备的锂基膨润土在醇溶剂中悬浮性良好,可缩短铸造涂料的生产周期,并降低生产成本。     

Effects of Post-weld Heat Treatment on Microstructure,Mechanical Properties and the Role of Weld Reinforcement in 2219 Aluminum Alloy TIG-Welded Joints

In as-welded state, each region of 2219 aluminum alloy TIG-welded joint shows diff erent microstructure and microhardness due to the diff erent welding heat cycles and the resulting evolution of second phases. After the post-weld heat treatment, both the amount and the size of the eutectic structure or θ phases decreased. Correspondingly, both the Cu content in α-Al matrix and the microhardness increased to a similar level in each region of the joint, and the tensile strength of the entire joint was greatly improved. Post-weld heat treatment played the role of solid solution strengthening and aging strengthening. After the post-weld heat treatment, the weld performance became similar to other regions, but weld reinforcements lost their reinforcing eff ect on the weld and their existence was more of an adverse eff ect. The joint without weld reinforcements after the post-weld heat treatment had the optimal tensile properties, and the specimens randomly crack in the weld zone.     

The First Phase of the SRIF Industrialized Base in ＂West Area＂ Has Been Put into Operation

After nearly two years＇ tense construction, the first phase of industrialized base of Shenyang Research Institute of Foundry （SRIF）, located at the Tiexi Casting and Forging Industrial Park in the west of Tiexi District, has now been completed and formally put into operation.     

Thermodynamics Study on the Decomposition of Chromite with KOH

Institute of Process Engineering, Chinese Academy of Sciences, China, has proposed a method for oxidative leaching of chromite with potassium hydroxide. Understanding the mechanism of chromite decomposition, especially in the potassium hydroxide fusion, is important for the optimization of the operating parameters of the oxidative leaching process. A traditional thermodynamic method is proposed and the thermal decomposition and the reaction decomposition during the oxidative leaching of chromite with KOH and oxygen is discussed, which suggests that chromite is mainly destroyed by reactions with KOH and oxygen. Meanwhile, equilibrium of the main reactions of the above process was calculated at different temperatures and oxygen partial pressures. The stable zones of productions, namely, K2CrO4 and Fe2O3, increase with the decrease of temperature, which indicates that higher temperature is not beneficial to thermodynamic reactions. In addition, a comparison of the general alkali methods is carried out, and it is concluded that the KOH leaching process is thermodynamically superior to the conventional chromate production process.     

Influence of Heat Treatment on Damping Behaviour of the Magnesium Wrought Alloy AZ61

The effect of isochronal heat treatments for 1h on variation of damping, hardness and microstructural change of the magnesium wrought alloy AZ61 was investigated. Damping and hardness behaviour could be attributed to the evolution of precipitation process. The influence of precipitation on damping behaviour was explained in the framework of the dislocation string model of Granato and Lücke.     

Effect of Rare Earth Doping on Impedance,Modulus and Conductivity Properties of Multiferroic Composites:0.5(BiLa_xFe_(1-x)O_3)–0.5(PbTiO_3)

The Lanthanum-doped bismuth ferrite–lead titanate compositions of 0.5(Bi LaxFe1-xO3)–0.5(Pb Ti O3)(x = 0.05,0.10,0.15,0.20)(BLxF1-x-PT) were prepared by mixed oxide method.Structural characterization was performed by X-ray diffraction and shows a tetragonal structure at room temperature.The lattice parameter c/a ratio decreases with increasing of La(x = 0.05–0.20) concentration of the composites.The effect of charge carrier/ion hopping mechanism,conductivity,relaxation process and impedance parameters was studied using an impedance analyzer in a wide frequency range(102–106Hz) at different temperatures.The nature of Nyquist plot confirms the presence of bulk effects only,and non-Debye type of relaxation processes occurs in the composites.The electrical modulus exhibits an important role of the hopping mechanism in the electrical transport process of the materials.The ac conductivity and dc conductivity of the materials were studied,and the activation energy found to be 0.81,0.77,0.76 and 0.74 e V for all compositions of x = 0.05–0.20 at different temperatures(200–300 °C).     

Quantitative Analysis of the Crystallographic Orientation Relationship Between the Martensite and Austenite in Quenching–Partitioning–Tempering Steels

The orientation relationships(ORs)between the martensite and the retained austenite in low-and medium-carbon steels after quenching–partitioning–tempering process were studied in this work.The ORs in the studied steels are identified by selected-area electron diffraction(SAED)as either K–S or N–W ORs.Meanwhile,the ORs were also studied based on numerical fitting of electron backscatter diffraction data method suggested by Miyamoto.The simulated K–S and N–W ORs in the low-index directions generally do not well coincide with the experimental pole figure,which may be attributed to both the orientation spread from the ideal variant orientations and high symmetry of the low-index directions.However,the simulated results coincide well with experimental pole figures in the high-index directions{123}_(bcc).A modified method with simplicity based on Miyamoto’s work was proposed.The results indicate that the ORs determined by modified method are similar to those determined by Miyamoto’method,that is,the OR is near K–S OR for the low-carbon Q–P–T steel,and with the increase of carbon content,the OR is closer to N–W OR in medium-carbon Q–P–T steel.     

Growth Kinetics of Single Inclusion Particle in Molten Melts

On the basis of the single-particle framework, a new theory on inclusion growth in metallurgical melts is developed to study the kinetics of inclusion growth on account of reaction and collision. The studies show that the early growth of inclusion depends on reaction growth and Brawnian motion collision, and where the former is decisive, the late growth depends on turbulence collision and Stokes＇ collision, and where the former is dominant; collision growth is very quick during the smelting process, lessened in the refining process, but nearly negligible in the continuous casting process.     

Theoretical Analysis for the Motion and Temperature of Melt Droplets in Spray Degassing Process

The motion of melt droplets in spray degassing process was analyzed theoretically. The height of the treatment tank in spray degassing process could be determined by the results of theoretical calculation of motion of melt droplets. To know whether the melt droplets would solidify during spraying process, the balance temperature of melt droplets was also theoretically analyzed. Then proof experiments for theoretical results about temperature of melt droplets were carried. In comparison, the experimental results were nearly similar to the calculation results.     

Using Finite Element and Contour Method to Evaluate Residual Stress in Thick Ti-6Al-4V Alloy Welded by Electron Beam Welding

This work was to reveal the residual stress profile in electron beam welded Ti-6Al-4V alloy plates(50 mm thick) by using finite element and contour measurement methods.A three-dimensional finite element model of 50-mmthick titanium component was proposed,in which a column–cone combined heat source model was used to simulate the temperature field and a thermo-elastic–plastic model to analyze residual stress in a weld joint based on ABAQUS software.Considering the uncertainty of welding simulation,the computation was calibrated by experimental data of contour measurement method.Both test and simulated results show that residual stresses on the surface and inside the weld zone are significantly different and present a narrow and large gradient feature in the weld joint.The peak tensile stress exceeds the yield strength of base materials inside weld,which are distinctly different from residual stress of the thin Ti-6Al-4V alloy plates presented in references before.     

Microstructures and Tensile Properties of Ultrafine-Grained Ni–(1–3.5) wt% SiC_(NP) Composites Prepared by a Powder Metallurgy Route

Silicon carbide nanoparticle-reinforced nickel-based composites(Ni–Si CNP),with a Si CNPcontent ranged from1 to 3.5 wt%,were prepared using mechanical alloying and spark plasma sintering.In addition,unreinforced pure nickel samples were also prepared for comparative purposes.To characterize the microstructural properties of both the unreinforced pure nickel and the Ni–Si CNPcomposites transmission electron microscopy(TEM) was used,while their mechanical behavior was investigated using the Vickers pyramid method for hardness measurements and a universal tensile testing machine for tensile tests.TEM results showed an array of dislocation lines decorated in the sintered pure nickel sample,whereas,for the Ni–Si CNPcomposites,the presence of nano-dispersed Si CNPand twinning crystals was observed.These homogeneously distributed Si CNPwere found located either within the matrix,between twins or on grain boundaries.For the Ni–Si CNPcomposites,coerced coarsening of the Si CNPassembly occurred with increasing Si CNPcontent.Furthermore,the grain sizes of the Ni–Si CNPcomposites were much finer than that of the unreinforced pure nickel,which was considered to be due to the composite ball milling process.In all cases,the Ni–Si CNPcomposites showed higher strengths and hardness values than the unreinforced pure nickel,likely due to a combination of dispersion strengthening(Orowan effects) and particle strengthening(Hall–Petch effects).For the Ni–Si CNPcomposites,the strength increased initially and then decreased as a function of Si CNPcontent,whereas their elongation percentages decreased linearly.Compared to all materials tested,the Ni–Si CNPcomposite containing 1.5% Si C was found more superior considering both their strength and plastic properties.