等离子体喷涂羟基磷灰石涂层的化学不均匀性

采用等离子喷涂法制备了羟基磷灰石(HA)涂层,将涂层沿平行和垂直表面方向抛光试样表面,用电子探针微分析仪和X射线衍射仪等手段研究了试样的显微组织、成分分布和相组成等. 结果表明, 等离子喷涂HA涂层中存在化学成分和相组成等的不均匀性,表现为显微组织中衬度的差别. 其中低磷、低氧区主要由非晶相、分解相和重结晶相组成. 等离子喷涂时,HA粉末颗粒内外熔融程度的差异导致涂层相组成的不均性. 热处理可消除涂层组分的不均匀性,但会导致涂层内部裂纹的产生或扩展.     

碳——锰原子对在奥氏体高锰钢中的作用

根据奥氏体高锰钢的内耗试验，动态应变时效，价电子结构计算和Ｆｅ２Ｍｎ２Ｃ原子团的设想等结果，综述并分析了其微观结构及碳－－锰原子对的作用。     

送粉方式对碳/碳基体上等离子喷涂羟基磷灰石涂层的影响

采用等离子喷涂技术在碳／碳复合材料上制备了羟基磷灰石(HA)涂层，采用扫描电镜、X射线衍射仪、电子探针和电子拉伸机等研究了送粉方式对HA涂层的组织与性能的影响。结果表明：内送粉方式下制得的HA涂层，颗粒熔化程度较高，涂层的晶相含量较低；40kW的喷涂功率和外送粉方式下制得的HA涂层与碳／碳基体的抗剪强度最高；但HA涂层与碳／碳基体之间仍属于机械结合。     

C-Mn segregation and its effect on phase transformation and deformation in Fe-Mn-C alloys

C-Mn segregation and its effect on phase transformation and plastic deformation in Fe-Mn-C alloys were studied through the calculation of valence electron structure, the microregion composition detection and TEM in-situ dynamic tensile deformation test The experimental results show that in Fe-8Mn-1.2C alloyed austenite, nA of units with C Mn involved is 3 98 times that of units without C involved and 1.4 times that of units with C involved; aCD of units with C-Mn involved is 2 21 times that of units with C involved. In Fe-Mn-C alloyed austenites, there exists microsegrcgation of C-Mn, forming the randomly distributed Fe-Mn-C atomic cluster segregation zone linked with the -C-Mn-C-Mn- strong bond network, which will effectively slow down the motion of atoms and retard the initiation of the slip system and the movement of dislocation, and thus will severely influence the phase transformation and deformation of the alloy     

钛、镁、铝合金的表面微弧氧化技术

综述了微弧氧化这种新技术制备金属表面陶瓷层的原理和规律，分析了钛、镁、铝合金通过微弧氧化技术制备表面多孔生物陶瓷材料的可行性及现状，指出了研究中的不足和对未来应用的展望。     

烧结对羟基磷灰石微球微观结构和性能的影响

利用扫描电镜(SEM)、激光粒度分析仪(LDPSA)、X射线衍射仪(XRD)以及比表面积分析仪(SSA)等检测方法,研究了烧结对于羟基磷灰石微球的微观结构、形貌以及粒径、比表面积和孔隙率等性能的影响.结果表明,经800℃热处理,微球的比表面积、孔隙率及其表面形貌均会发生明显的变化;经1000℃烧结后,部分羟基磷灰石相发生热分解,生成较多的的杂质相,如α-磷酸三钙(α-TCP)和β-磷酸三钙(β-TCP).     

热处理和SBF浸泡对羟基磷灰石涂层力学性能的影响

利用X射线衍射仪(XRO)、电子探针(EPMA)、扫描电镜(SEM)等检测手段,研究了等离子喷涂羟基磷灰石(HA)涂层热处理前后的显微组织变化,以及经热处理和模拟体液(SBF)浸泡处理对涂层力学性能的影响.结果表明:涂层内部衬度不一,存在化学非均匀性.涂层中的裂纹、气孔、未熔颗粒界面是断裂的起源.热处理能使涂层中的不均匀性消失,成分趋于一致,结晶度提高.热处理后,粗颗粒涂层结合强度升高而细颗粒涂层则降低.0.5 SBF浸泡处理后,所有涂层的结合强度都降低,原始细颗粒涂层降低幅度最大,原始粗颗粒涂层次之,热处理细涂层降低幅度最小.     

Cross-sectional analysis on microstructure of plasma-sprayed HA＋TiO2 composite coatings on titanium substrate

The cross-sectional analysis on hydroxyapatite (HA) coating and HA TiO2 composite coating was conducted by using electron probe microanalyser (EPMA). The results reveal that annealing at 650℃ leads to the cracking within the HA coating or along the coating/substrate interface. The ribbon-like regions in HA coating are verified to contain less PO4^4- groups resulted from the high temperature melting of HA particles in plasma flame. From the viewpoint of microstructural observation, it can be concluded that the addition of TiO2 into HA coating can effectively strengthen and toughen the whole coating system with a shift of the well-bonded interface from the THA (top HA) coating/HTBC (HA TiO2 bond coat) interface in the as-sprayed THBC (top HA-HTBC) coating to the HTBC/Ti substrate interface in the heat treated THBC coating. The THA coating bonds well to Ti substrate per-haps via its TiO2 hobnobbing with the Ti oxides formed on the Ti substrate.     

粉末冶金多孔钛表面生物活化的研究

采用粉末冶金法制备了具有适合人体组织长入孔径的多孔钛,并对其进行生物活化处理.利用EPMA、SEM、XRD等研究了不同预处理方法和浸泡时间对多孔钛表面羟基磷灰石(HA)的形貌及形成速度的影响.结果表明,多孔钛的表面以及孔的内表面上均有纳米晶TiO2生成,预钙化处理能够明显提高多孔钛表面生成羟基磷灰石的速率,促进HA的形核长大,预钙化后磷含量增加明显,验证了Na2HPO4在预处理中对多孔钛的活化是有利的.     

预应力热处理对羟基磷灰石涂层相组成和结合强度的影响

设计不同角度的斜面工业纯钛柱,采用等离子法制备羟基磷灰石涂层,设计工装使涂层在预加相同正应力和不同切应力条件下进行热处理.利用电子拉伸实验机进行剪切结合强度测试,利用X射线衍射仪检测涂层的相组成与结晶度,探讨应力条件下热处理对涂层组成和涂层/基体结合强度的影响.研究表明:热处理中预加应力可以提高涂层的结晶度和涂层/基体的剪切结合强度.