酸碱处理对磷酸盐激光玻璃表面的侵蚀研究

通过添加重金属钡的酸碱溶液, 在不同外界条件下, 研究了磷酸盐激光玻璃表面结构在酸碱侵蚀过程的反应机理. 结果表明, 酸碱对磷酸盐激光玻璃的侵蚀过程主要包括金属阳离子析出和[PO₄]网络结构破坏等两个重要过程. 金属阳离子的析出主要是非桥氧结构P-O-M(M为K⁺、Ba²⁺、Al³⁺等阳离子)在酸碱作用下生成P-O-H基团, 而[PO₄]网络结构的破坏则是指玻璃网络原有的Q²结构在酸碱的侵蚀下逐渐向Q¹和Q⁰转变. 据此, 推导了磷酸盐激光玻璃在酸碱侵蚀过程中的反应模型.     

一种显示马氏体不锈钢组织的金相侵蚀剂

介绍了用氢氟酸、硝酸水溶液侵蚀剂侵蚀马氏体不锈钢，侵蚀速度快且侵蚀试面清澈，避免了氯化高铁、盐酸水溶液对侵蚀面造成的污迹缺陷。     

高掺量稀土磷酸盐玻璃化学稳定性的研究

稀土掺杂的磷酸盐玻璃作为激光介质和特种光学玻璃材料,其化学稳定性研究是至关重要的.本文主要研究了掺加10mo1%和15mo1%Sm2O3的P2O5-BaO-Al2O3体系玻璃的化学稳定性,研究结果表明:玻璃的耐水性能受玻璃中离子含量的影响较大,Al3 和Sm3 离子的含量越高,结构越稳定,耐水性能越好;玻璃的耐酸性能与结构中阳离子的极化能力(Z2/r)有关,Z2/r越大,耐酸性能越好,而且玻璃的侵蚀是渐缓的,这是由于玻璃表面形成了一层明显的覆盖层所致;玻璃在碱性介质中的侵蚀机理是磷酸盐长链末节的金属离子被水化,产生P-O-P断键,形成正磷酸盐溶解到溶液中,同时,随着稀土离子的增加,耐碱性能变差.     

硬铝合金的侵蚀方法及技巧

针对硬铝合金样品组织显示困难及第二相侵蚀脱落等问题，提出了合理选择侵蚀剂、控制侵蚀过程出现的气泡逸出、注意侵蚀结束前的表面清洁和严格掌握侵蚀时间等方法。     

铝箔坯料晶粒的显示和测定

用混合的强酸侵蚀铝箔坯料表面，通过显微观察及数码摄影技术，可准确检测铝箔坯料的晶粒大小，与常规的图片比较法相比，提高了晶粒测定的准确度。     

某钢管厂热浸锌钢板锅锌液侵蚀原因分析

某厂热浸锌钢板锅因锌液侵蚀破坏较为严重,每年因锌锅侵蚀造成经济损失竟达八、九百万元,是该厂急需解决的问题;亦是国内热浸锌行业中普遍存在的问题。本文通过该厂的现场调查,对锌锅的侵蚀原因进行了理论分析,并提出防止锌锅侵蚀、延长使用寿命的可行方案,对解决锌锅侵蚀问题具有一定的实际意义。     

水泥混凝土硫酸盐侵蚀综述

从化学反应的角度详细介绍了水泥混凝土的硫酸盐侵蚀机理及其相应的侵蚀产物,分别从内部和外部两方面阐述了硫酸盐侵蚀的因素,论述了目前抗硫酸盐侵蚀的一些方法以及这些方法的优劣性,并展望了水泥混凝土抗硫酸盐侵蚀的前景。     

一种侵蚀高锰钢的方法

用于侵蚀高锰钢的化学侵蚀剂种类比较多，在不同的资料中有不同的介绍和规定。文献[1]中认为硝酸酒精溶液、氯化铁硝酸水溶液（氯化铁200g＋硝酸300mL＋水100mL）均可用作高锰钢的侵蚀剂；在GB13925（（铸造高锰钢金相》中规定的侵蚀剂有4％硝酸酒精溶液、甘油混合酸（HNO3：HCl：甘油=1：2：3）和过饱和苦昧酸溶液三种。目前比较常用的侵蚀方法是用4%硝酸酒精溶液和4％的盐酸酒精溶液反复擦蚀。以上侵蚀剂和侵蚀方法在实际应用中操作繁琐、效果不满意。笔者在高锰钢的日常检验中使用了一种操作简便、显示效果真实的热浸蚀方法，具体操作如下：     

金属间化合物MoSi2的晶界侵蚀方法研究

对两种MoSi2材料试样进行了侵蚀试验。利用XJG-04型金相显微镜和扫描电子显微镜，研究了MoSi2侵蚀后的显微组织，并对其侵蚀结果进行了探讨。研究发现，MoSi2基材料具有晶间腐蚀敏感性，采用HF HNO3 H2O作为其晶界侵蚀剂是可行的。     

硫酸盐侵蚀下石膏的形成及破坏机制研究现状

硫酸盐侵蚀是影响水泥基材料耐久性的重要因素,它不仅会缩短材料的服役寿命,甚至可能危及结构安全。在硫酸盐侵蚀过程中,钙矾石、石膏和碳硫硅钙石等侵蚀产物不断形成,从而导致材料出现膨胀、开裂、软化和剥落等不同形式的破坏。由于不同侵蚀产物的形成条件和对水泥基材料的侵蚀机理存在明显差异,而侵蚀机理是工程实践中指导预防硫酸盐侵蚀的重要依据,因此探明不同侵蚀产物的形成及稳定条件以及各侵蚀产物对材料的作用机理成为该研究课题的主要内容。 从现有研究来看,钙矾石型硫酸盐侵蚀是目前研究最为成熟的一种硫酸盐侵蚀。钙矾石是在高碱性硫酸盐溶液条件下形成的主要侵蚀产物,并且当其在狭小封闭的孔洞中生长时会导致材料发生膨胀、开裂破坏,相应的膨胀机理有吸水肿胀理论、结晶压理论和固相反应理论等。另外,在钙矾石型硫酸盐侵蚀的预防方面,发现通过控制水泥中铝酸三钙含量可有效减小因钙矾石形成而造成的膨胀危害。近年来,世界各地的研究者竞相报道了碳硫硅钙石的形成对混凝土结构造成严重破坏的工程实例,这使得碳硫硅钙石型硫酸盐侵蚀也逐渐受到重视。目前普遍认为碳硫硅钙石的形成主要导致材料出现泥化和分解现象,但其形成条件较为复杂,只在一些特殊环境下才有可能发生。 石膏是水泥基材料在硫酸盐侵蚀下形成的另一种较为常见的腐蚀产物,它的形成同样影响着水泥基材料的耐久性能。研究发现,硫酸盐溶液浓度越高,越利于形成石膏,但后来发现溶液pH值对石膏的形成及稳定影响更为显著,同时溶液温度、离子种类以及腐蚀制度等对石膏的形成也有一定影响。由于石膏的化学组成相对简单且不含铝相,因此采用普通抗硫酸盐侵蚀方法并不能有效抑制石膏的形成及破坏。石膏的形成往往伴随着水化产物的溶解脱钙,从而导致材料出现软化和剥落现象,但在石膏的膨胀问题上仍存在较大争议。 本文综述了硫酸盐侵蚀下水泥混凝土中石膏形成的影响因素,总结了石膏的生长位置及其引起的脱钙作用,最后对石膏的膨胀作用进行了相关探讨。     

镁合金表面纳米二氧化铈/磷酸盐复合转化膜的制备及其防护性能

添加纳米颗粒可改善金属表面膜层的性能,但目前添加纳米颗粒改善镁合金表面磷化膜性能的报道较少。通过向磷化处理液中添加纳米二氧化铈(nano-CeO_2)颗粒在镁合金表面制备了一层纳米二氧化铈/磷酸盐复合转化膜,采用X射线衍射仪(XRD)、X射线光电子能谱(XPS)、电化学阻抗谱(EIS)和极化曲线等手段研究了添加nano-CeO_2颗粒对膜层成分和防护性能的影响,讨论了nano-CeO_2颗粒的作用机制。结果表明:复合转化膜的相成分为Zn_3(PO_4)_2·4H_2O、Zn_2Mg(PO_4)_2和CeO_2,在单组分磷化膜成分的基础上多出了CeO_2相。在硼酸缓冲溶液中,单组分磷化膜的膜层电阻(R_c)和低频阻抗值(R_(0.01 Hz))分别为561.74 kΩ·cm~2和938.11 kΩ·cm~2,而复合转化膜的R_c和R_(0.01 Hz)分别为2 428.98 kΩ·cm~2和3 985.61 kΩ·cm~2;与此同时,覆盖复合转化膜镁合金的腐蚀电流密度为4.05×10~(-7)A/cm~2,而覆盖单组分磷化膜镁合金的为8.38×10~(-6)A/cm~2,R_c和R_(0.01 Hz)的增大以及J_(corr)的减小说明复合转化膜的防护作用明显优于单组分磷化膜的防护作用。nano-CeO_2颗粒的作用机制主要归因于两个方面:第一,nano-CeO_2颗粒在处理液中的添加有利于磷酸盐晶核的形成;第二,nano-CeO_2颗粒作为一种不溶性固体粒子在膜层中的存在可以强化膜层的物理屏蔽效应。     

Ca-(Mg)-Sialon陶瓷的水基润滑研究

利用SRV球-盘磨损实验机考察了Sialon陶瓷在空气、水及三种钠盐溶液中的摩擦学性能,并用X光电子能借（XPS）揭示了摩擦化学反应对Sialon陶瓷摩擦学性能的影响．研究表明,在空气及水中,CM-60（（Ca,Mg）-α-Sialon）都具有比C-60（Ca-α-Sialon）好的抗磨性;水降低了两种Sialon陶瓷（CM-60和C-60）的摩擦系数,但增大了其磨损体积．CM-60在三种钠盐溶液中的磨损体积顺序为：硝酸钠＞磷酸钠＞次亚磷酸钠;CM-60在三种钠盐溶液及水中的摩擦系数顺序为：硝酸钠＞水＞次亚磷酸钠＞磷酸钠．XPS分析表明,水同Sialon陶瓷表面氧化物的反应,造成了陶瓷的腐蚀磨损,从而,在水及盐溶液中,Sialon陶瓷的磨损体积都有所增加．     

溶胶凝胶法制备磷酸锆钠陶瓷材料

以Zr(NO3)4.5H2O、NH4H2PO4和NaNO3为原材料,采用溶胶凝胶法合成了磷酸锆钠(NaZr2(PO4)3)陶瓷粉体,采用TG-DTA,XRD和SEM测试方法对粉体性能进行了表征,研究了烧结温度和pH值等反应条件对粉体合成的影响.结果表明,要获纯的磷酸锆钠粉体,合成温度需控制在800～1 000℃之间,其中最合适合成温度为900℃左右.前驱体pH值对合成温度基本没有影响,但会影响产物微观形貌.当合成温度为900℃,pH值为9时可以制备出团聚较少、颗粒均匀、分散性较好且平均粒径为100nm的磷酸锆钠粉体.     

Analysis of the structural changes of a phosphate glass during its dissolution in simulated body fluid

The structural changes of two calcium–sodium metaphosphate glasses during its dissolution in simulated body fluid (SBF) have been analyzed by Fourier transform Raman spectroscopy (FT-Raman), scanning electron microscopy (SEM) and environmental scanning electron microscopy (ESEM). The results showed that no structural changes could be detected during the first week of dissolution. However, after approximately 4 weeks of dissolution the analysis of the glass surface revealed the presence of a thin orthophosphate layer. The elemental analysis of this layer by X-ray dispersive energy showed the presence of calcium phosphate ions, while almost no sodium was detected. The observation of the glasses by ESEM showed the formation of small crystals when the water vapor pressure of the chamber was decreased. This indicates that the layer analyzed by SEM and FT-Raman was related to a hydrated calcium phosphate layer.     

Synthesis of Submicron Са3–хNa2х(PO4)2 Substituted Calcium Phosphate Powders in a Nonaqueous Medium for Stereolithographic Fabrication of Bioceramics

Inorganic Materials - This paper compares the synthesis of tricalcium phosphate (TCP) (β-Са3(РО4)2) and Са3–хNa2х(PO4)2 substituted...     

Influence of the heat treatment procedure and irradiation on the structure of the anionic motif and crystallization of uranium-containing phosphate glasses

The solubility of UO₃ in sodium almino(ferro)phosphate (SAFP) glasses prepared by quenching of melts reaches almost 50 wt %. The structure of the anionic motif of the network of such glasses is formed by polyanions and consists of alumino(ferro)phosphate and uranium–oxygen constituents. Irradiation with electrons of up to 8 MeV energy to an absorbed dose of 10⁶ Gy does not lead to appreciable changes in the glass structure, except insignificant increase in the fraction of octahedrally coordinated aluminum. After annealing, samples of sodium aluminophosphate glasses with low content of uranium oxides (up to 10 wt %) partially crystallize with the formation of phosphotridymite, whereas high-uranium glasses (up to ~50 wt % UO₃) remain X-ray amorphous. Samples of SAFP glasses at low concentrations of uranium oxides remain amorphous and at high concentrations undergo phase segregation with the formation of a SAFP glass phase enriched in uranium oxides and crystalline phase of sodium aluminum iron orthophosphate Na₃(Al,Fe)₂(PO₄)₃ containing impurity amounts of uranium ions. The incorporation of uranium ions is most probably due to the occurrence of redox processes between uranyl and iron ions.     

以石英为原料制备白炭黑的实验研究

为研究白炭黑的制备工艺,以石英原矿、浓硫酸、Na2CO3和NaOH为原料,利用煅烧-淬冷-硫酸酸洗工艺制备质量分数大于99%的高纯石英粉,并利用煅烧-沉淀法制备非晶白炭黑。采用X射线荧光(XRF)和X射线衍射(XRD)等手段研究钠源(Na2CO3)与石英比例、不同钠源(NaOH)等对白炭黑品质的影响。结果表明:将石英与Na2CO3或NaOH混合煅烧后制成溶液,通入CO2气体后可生成非晶白炭黑,最佳工艺条件为:n(Na2CO3)∶n(SiO2)=1∶1,混合物在1 250℃下煅烧2.5 h。     

低温快速电化学辅助磷化膜的制备及其耐蚀性

目前国内外关于电化学辅助磷化的研究报道较少。采用硫酸铜点滴试验、塔菲尔极化曲线研究了电化学辅助制备磷化膜的耐蚀性,探究电化学辅助磷化的最佳配方及工艺条件。通过单因素试验优化磷化液组分,通过正交试验优化工艺条件。结果表明,电化学辅助可以显著降低磷化温度、缩短磷化时间、减少磷化渣,优选出的磷化液组成为:5.00 g/L ZnO,13.00 mL/L磷酸(85%),20.00 g/L Zn(NO_3)_2·6H_2O,1.00 g/L酒石酸钾钠,1.00 g/L NH_4HF_2,1.20 g/L NaClO_3,5.00 g/L磷酸二氢锌,0.08 g/L CuSO_4;最优工艺参数为电流密度1.2 A/dm~2,温度35℃,通电时间7 min。最优工艺下所得磷化膜耐硫酸铜点滴试验时间达860 s;磷化时间1 min时,所得磷化膜硫酸铜点滴试验耐蚀性为61 s(远优于化学磷化的19 s),磷化膜外观均匀、致密。     

Processing,characterisation, and biocompatibility of zinc modified metaphosphate based glasses for biomedical applications

Bulk and structural properties of zinc oxide (0 up to 20 mol%) containing phosphate glasses, developed for biomedical applications, were investigated throughout this study using differential thermal analysis (DTA), differential scanning calorimetry, X-ray powder diffraction and 31P and 23Na MAS NMR. Surface wettability and MG63 viability were also considered for surface characterisation of these glasses. The results indicated that incorporation of zinc oxide as a dopant into phosphate glasses produced a significant increase in density; however, the thermal properties presented in glass transition, and melting temperatures were reduced. NaZn(PO3)3 was detected in the X-Ray Powder Diffraction Analysis (XRD) trace of zinc containing glasses, and the proportion of this phase increased with increasing zinc oxide content. NaCa(PO3)3 as a second main phase and CaP2O6 in minor amounts were also detected. The 31P and 23Na MAS NMR results suggested that the relative abundances of the Q1 and Q2 phosphorus sites, and the local sodium environment were unaffected as CaO was replaced by ZnO in this system. The replacement of CaO with ZnO did seem to have the effect of increasing the local disorder of the Q2 metaphosphate chains, but less so for the Q1 chain-terminating sites which were already relatively disordered due to the proximity of modifying cations. Glasses with zinc oxide less than 5 mol% showed higher surface wettability, while those with 5 up to 20 mol% showed comparable wettability as zinc oxide free glasses. Regardless of the high hydrophilicity and surface reactivity of these zinc oxide containing glasses, they had lower biocompatibility, in particular 10-20 mol% ZnO, compared to both zinc free glasses and Thermanox. This may be associated with the release of significant amount of Zn2+ enough to be toxic to MG63.     

Multifunctional microsized modified kaolin and its application in wastewater treatment

The multifunctional microsized ZnO-PO(4)(3-)-modified kaolin of average diameter about 500nm with the composition Na(2)O:ZnO:Na(3)PO(4):SiO(2):Al(2)O(3)=2.5-8.5:0.04-0.65:0.8-4.5:1.5-2.5:1 (molar ratio) were firstly synthesized from ZnO, Na(3)PO(4), NaOH and kaolin and characterized by standard techniques, its application in oilfield produced wastewater purification was also studied. It was found that the physical properties of ZnO-PO(4)(3-)-modified kaolin such as specific surface area, porous volume and pore diameter increased independently compared to the starting kaolin. It was also found that the prepared kaolin has multifunctional properties to decrease COD and BOD value, remove scaling ion (Fe(n+), Ca(2+) and Mg(2+)), improve MF, decrease bacteria and inhibit corrosion and can be used effectively in oilfield wastewater purification.