探析镁与碱性盐溶液反应的复杂性与可行性——以镁与碳酸钠溶液反应为例

一次验证镁与NaHCO3溶液反应得到H2的实验中,发现镁能与饱和Na2CO3溶液作用持续释出H2,为此通过分析Mg/H2O体系的热力学数据和研究其动力学机理认为实现镁与水溶液作用能持续释出H2的有效方法:在溶液中加入能破坏氢氧化镁保护层的某些离子。并设计有关实验证明:在碱性溶液中,若加入能与Mg^2+形成稳定配合物的其他阴离子(如甘氨酸根离子、草酸根离子、EDTA等),则镁就能与碱性的盐溶液持续反应。

基于“动手学”理念的“盐溶液的酸碱性”教学实录

记录了＂盐溶液的酸碱性＂的课堂教学过程,分析了每个教学环节的设计意图,通过＂镁粉与氯化铵溶液反应＂演示实验引出课题,通过＂动手学＂构建盐类水解的知识体系,最后运用所学新知解决问题,呼应课首,实践了＂动手学＂的教学理念。

温度对盐溶液酸碱度的影响探析

文章利用pH传感器探究了温度对三种盐溶液pH的影响,得出了盐溶液pH和pOH随温度的变化规律。分析利用pH表征溶液酸碱性的局限性,厘清学习过程产生的迷思概念。

锌钴合金防腐蚀镀层的研究与应用

在碱性锌酸盐溶液中获得的含钴量 0 6 %～ 1%的锌钴合金镀层 ,耐中性盐雾腐蚀时间比镀锌层高 3～ 5倍 ,耐大气腐蚀性比镀锌层高 10倍以上 ,这种锌钴合金镀层的耐大气腐蚀性比含镍量 8%～ 13%的锌镍合金镀层还高 1倍以上 ,可显著提高工件的耐蚀性。

Effects of additives on zinc electrodeposition from alkaline zincate solution

The effects of additives on the surface and cross-sectional morphologies of zinc deposits on iron substrate from alkalinezincate solution were characterized by scanning electron microscope(SEM).The cathodic reaction mechanisms under variousconcentrations of additives were investigated using cyclic voltammetry(CV)and electrochemical impedance spectroscopy(EIS)techniques.It is found that with increasing the additive A content in the bath solution,the nucleation overpotential(NOP)value isobviously increased and the inhibition effect is strengthened.This may be mainly due to the adsorption of additive A on the cathodicelectrode surface,which can cover the active sites and block the discharge reduction.The results of EIS analysis indicate that therate-determining step of zinc electrodeposition process is changed from mixed control step into electrochemical reduction step in thepresence of additive A.However,any quantity of additive B has little effect on the NOP value and the inhibition effect is not obvious.Furthermore,addition of additive A and additive B at the same time displays the strongest inhibition effect and shows a strongsynergism because of their co-adsorption on the cathodic electrode surface.

Kinetics of Zn cathodic deposition in alkaline zincate solution

Kinetic parameters of the electrode reactions were measured by investigating steady-state current-potential behaviors. The Tafel slopes of cathodic and anodic processes are -0.113 8 V and -0.041 18 V, the anodic and cathodic apparent transfer coefficients are 0.519 3 and 1.435 2, respectively, and the stoichiometric number of rate-deterrnining step is 1. The theoretical kinetics equation of electrode reaction was deduced, from which the dynamic parameters can be calculated as follows： the cathodic and anodic Tafel slopes are -0.118 V and -0.039 4 V, respectively, consisting with the experimental values, Finally, the correctness of the mechanism was further demonstrated using apparent transfer coefficient according to the electrochemical dynamic equation of multi-electron reaction.

平衡常数的妙用

平衡思想是07版普通高中化学课程标准中提出的化学学科核心素养之一,是新高考重点考查的素养,平衡常数则是平衡思想"王冠"上最璀璨的明珠,是定量化研究平衡的抓手,也是高中生学习中的难点之一,充分地认识并掌握好平衡常数的有关知识显得尤为重要。为此很有必要深挖平衡常数的潜在价值,充分用好平衡常数这一重要工具,提高平衡思想教学的效果。

钛材的去氧化皮处理

所发明的钛材去氧化皮工艺为：将带有氧化物残渣的钛材浸入一种碱性熔融盐溶液中进行阳极电解处理或交流电电解处理，然后进行酸浸蚀处理，此溶液中不含氢氟酸。使用该工艺可以除去钛材表面的氧化物残渣，而不发生火花放电侵蚀现象，可用于钛及其合金的板材、管材、棒材和线材的去氧化皮处理。

Wettability and surfactivity of sodium phosphate surfactants in strong alkali solutions

The wettability,surfactivity and the correlation between wettability and surfactivity of sodium diethylhexylphosphate,sodium diethylhexyl polyoxyethylene phosphate and their complex in NaOH solutions were studied.A complex alkali resistant phosphate surfactant with good permeability was prepared.The wettability of surfactants was investigated by measuring the immersion time,sinking time and capillary effects of nature cotton grey fabric in NaOH solutions.The surfactivity of the surfactants was characterized by measuring the surface tension.The effect of the complex on the surface appearance of cotton grey fabric was also investigated with a scanning electron microscope(SEM) .The results show that all the surfactants exhibit good wettability for cotton grey fabric in 0.5-5.0 mol/L of NaOH solutions,the complex system exhibits better wettability in 5.0-7.0 mol/L of NaOH solutions,in comparison with either corresponding single surfactant component employed,and wettability is well correlative with the surfactivities of the surfactant.SEM images indicate that the cotton grey fabric is well wetted by the alkaline surfactant solution and the quality of fabric is improved.

矿用液压支架用耐蚀钢的研发

为解决矿井液压支架用钢由于服役环境复杂经常出现腐蚀的问题,设计开发了矿井液压支架用耐蚀钢,同时对其轧制及热处理工艺、组织性能、腐蚀行为等进行了研究。结果表明:采用中C,低P、S,复合添加Cr、Ni、Cu的化学成分设计,研发的Cr+Ni+Cu系耐蚀钢经模拟轧制、在线淬火后,在530℃保温1 h进行回火,组织为回火马氏体,力学性能最佳,抗拉强度和屈服强度分别为1 023、911 MPa,断后伸长率和断面收缩率分别为15%、55.9%,强度及塑韧性均满足国标要求且均较目前矿井用钢27SiMn有所提升;随着回火温度升高,实验钢中位错密度降低,强度逐渐下降,组织发生回复,马氏体板条边界变得模糊,带状结构消失,部分板条发生合并,尺寸变宽,由板条结构转变为块状,导致大角度晶界数量增多,塑韧性呈上升趋势;随着腐蚀的进行,实验钢腐蚀速率逐渐下降并趋于稳定,经240 h全浸腐蚀(碱性盐溶液)后,实验钢的年腐蚀速率为0.401 mm/a,相较于对比钢降低了40%,耐腐蚀性能良好;实验钢锈层主要为Fe(CrO_(4))OH,致密稳定,减少了溶液与基体的接触,提高了锈层对基体的保护能力。