Direct Electrolytic Preparation of Chromium Powder 正文:前言(例3) GEORGE Z CHEN, ELENA CORDO, and DEREK J FRAY Chromiun au pwler (Cr O))was Mp eas ow premed inta small cy lineal pelts which wer hun inten in air. The sintered peiken were wthe to a cument collector b form an awwmblod 通讯有长度的限制,因而前言必须简练 cuble. Constant-voltage (2.7 o 2k V)eclysis, with a graphite anod, was performed n olten 同时由于研究工作新,相关文献较少, 组mh时h面 因此也不需过多文字 ciency and nery constrain heing 75 pel and 5 Whkg, respectively, The fully hue pelt wery unform in sne, that tww with the eletnlywis timw. up to SO um(IS houn), The umiuu podul mophlewy (cubie crystallites) diller dras sally inm the isolar mwmhokgy shered in wher 专业性较强的全论文有两种 vannus cAnonial metal powkn A taluction mechamism is proposed. emplaning the Mrfuce metallization ad the early wage of elim lysis thmugh th poputation of the nctaloxile-glectnolyte three-phawe interline (pLl A.研究内容和结果较新,但由于专业 1. INTRODUCTION by hydrgen, anal can he ended and milled ink pwket Howewr, the millang prowas takes and only a long erna 性强,没有急迫发表的必要,且很难 PowDER metallurgy is penel to traditonal melling tion time, but it alw involves the risk ef ataminatan of allays containing metals of very diflerent reactivites, dn wut by cmtitunts fmn air and alo the mill 用通讯之类的短文章描述清楚。 sitie, and nting pin The saccess ef powder met. particle Mnes and wapeN, a wry tine menials are totally A类全论文的前言可与通讯的前言 四时个 I can he wn that the powlr particles have a great mumber M amgular wpea and very many aiflernd was,ran 同样对待(当然也可以更详细) als on industral scak. wach as alumimum However, there frum sabnicnometrs to a few km of minter still remain muny challenges for mak ing powders of high- This artcl epor ivy with the air emitte ms, wh as oxyyen, mitrogen, chomium powder dimly from wolalchmomitan oxid(Cn( 时h面止知kbdp,wh南kw(PP学m iaus many applications in nonlvrnus high-peifomne B.拓宽、纵深或跟踪等硏究,并有较多 alloys,sputter turget material lor plasma or wray coat 的相关文献。 以 Chroman has a melting lem B类全论文的前言应该有紧密切题的、mm种C物你 tI metal chemic (e.g IL, EXPERIMENTAL 较详细的背景介绍。 Al or Cal or ckctrolytie destraction) fuction, an (2) mechanical milling The darb gruen chanin oti (Cr 0)) power tse in le the high marke price of the manul (S to SI(Mg). The this wwk was supplie by Lonkon Scandinavian Mallu chromium pnwhnts by th exraction methods are hrinle, gical Ca Limitd ILSM. Rotherham, Sonth Yorthine,UK) particularly the electrolytic prout which is contaminated I hal a punny gruer thun 9)%pt und an regular, nxklike ntmifirn dsintull un of GORoIA CHIN Hewn, Is win he xhd of Cnan I a muge dd the rwr. All aher chemical were of tw ACS 该论文有1, pages:223-233,“ n2形 Leans MaNN s The Cr O pow kr was made into null cy lin 属于相当长的论文。 C=(如cmm图ps (1700 w IM)kg/mm) in a steel de and slip casing into nTALLRnl AL AND MAniIA nANsATIUNS D
该论文有11页，pages: 223-233， 属于相当长的论文。 正文：前言(例3) 通讯有长度的限制，因而前言必须简练。 同时由于研究工作新，相关文献较少， 因此也不需过多文字。 B. 拓宽、纵深或跟踪等研究，并有较多 的相关文献。 B类全论文的前言应该有紧密切题的、 较详细的背景介绍。 A. 研究内容和结果较新，但由于专业 性强，没有急迫发表的必要，且很难 用通讯之类的短文章描述清楚。 A类全论文的前言可与通讯的前言 同样对待（当然也可以更详细）。 专业性较强的全论文有两种：
正文:前言(例3)A类全论文前言 切题,指出一种普遍接受的观点。 切题,说明铬粉的用途,但不能用原子化法生产。 分析上述观点成立的条件 切题,介绍铬粉现有工业生产方法及高成本原因。 以这些条件考察一种成功的工业方 进一步分析铬粉现有工业生产方法高成本的原因, 法(原子化法),但指出其局限性。 并指出潜在质量问题。 L. INTRODUCTION 举实(图示)例证实现有工业生产铬粉的质量问题 POWDER metallurgy is preferred to traditional melting casting technologies for producing and processing metal alloys containing metals of very different reactivities, den 简述本研究一应用一种新电解方法制备铬粉及过 sities,and melting points. The success of powder met. 程机理。图示新电解方法及其工业名称的缘由 allurgy relies, to a great degree, on not only the quality of the powder product, but also the relative cost of the pro- duction process. The so-called atomization process has been by hydrogen. and can be crushed and milled into powder. als on industrial scale, such as aluminum IS However there tion time. bv milling process takes not only a long opera- successfully applied to a number of low-melting-point met- However. also involves the risk of contamination of still remain many challenges for making powders of high the powder product by constituents from air and also the mill melting-point metals particularly those having a high reac- tools. In addition, the milled powder has a wide range of tivity with the air constituents, such as oxygen, nitroge particle sizes and shapes, and very fine materials are usually and carbon dioxide. An example is chromium powder, which screened out and rejected. Figure I shows a typical example finds many applications in nonferrous high-performance of the commercial chromium powder prepared by milling utter target material for plasma or spray coat- It can be seen that the powder particles have a great number ing,and cermets, which are metal-ceramIc composites of of irregular shapes and very many different sizes, ranging high electric conductivity. thermal stability, and corrosion rom submicrometer to a few tens of micrometers. (oxidation) resistance. BAI Chromium has a melting tempera-: This article reports a novel electrolytic process for producing ture of 1857C. and, hence, chromium powder is very dif- .chromium powder directly from solid chromium oxide(Cr 03) ficult,if not impossible, to produce by the atomization . powder in molten CaCl2. Based on experimental evidence, a, powder involves two main steps: (D) metallothermic (e.g. .posed to account for the reduction process. The relevant work Al or Ca)or electrolytic (extraction) reduction, and followed a previously described electrolytic method for direct chromium products by these extraction methods are brittle. ematic representation of the process, which ure 2 shows a ch (2)mecnanical minng both contributing significantly electrochemical reduction of solid metal oxide (e.g TiO2)to to the high market price of the material ($6 to SIO/kg). The .the metal (e.g, Ti) in molten salts. -Fig ch is now called the● particularly the electrolytic product which is Fray. Farthing, and Chen Cambridge process by the industry
正文：前言(例3) 切题，指出一种普遍接受的观点。 分析上述观点成立的条件。 以这些条件考察一种成功的工业方 法（原子化法)，但指出其局限性。 切题，说明铬粉的用途，但不能用原子化法生产。 切题，介绍铬粉现有工业生产方法及高成本原因。 进一步分析铬粉现有工业生产方法高成本的原因， 并指出潜在质量问题。 举实(图示)例证实现有工业生产铬粉的质量问题。 简述本研究---应用一种新电解方法制备铬粉及过 程机理。图示新电解方法及其工业名称的缘由。 A类全论文前言
Available onine at wwso 正文:前言(例4) @ dAaa(000220201 B类全论文前言 该论文有14页,属于相当长的论文。 Toward optimisation of electrolytic reduction of solid chromium oxide to chromium powder in molten chloride salts Elena Gordo. George Z Chen.Derek J. Fray. cp,Gis 小朋bad回时la图 Toward optimisation of electolytic reduction of solid chromium 由叫 xide to chromium powder in molten chloride salts cmml pr ef the pellet B n tm repoed Elena Gerd Gerne Z Chen Derrk J. Fray +4%++( patend a wde cal Iwil a wew hat elare) batee t cable and n ab a pempie anaual itat n walawe swr w tw elem 你“包 tom wiochaomrmn withe pally toed onD) ts The mhermemle prawn w fo pims ee nadab Th aleatdywia hetal plls at we sale s tatu etten 0) ate en t fha of te ponte of pellet 4 To IsL N 语山 hallman ty a e mdlm s,la m地出 中的可 m 二一二 bea af taeniae! g descant n bH manahan af dhana the ai eia That 元二 dty标面Htp pee af al desion ef wwh The wel eleessht 时 be dael at peet. b a加 知出“心们 巴如/,如 邮时p b如 H%04+h四 the meal woe. frnm a 二们
正文：前言 ( 例4) B类全论文前言 该论文有14 页 ，属于相当长的论文
Available online at w encedirectcom 正文:前言(例4) 魔 口NG @ AECTROCHIMICA Cecora A(3004)219-2204 w轴w B类全论文前言 Toward optimisation of electrolytic reduction of solid chromium oxide to chromium powder in molten chloride salts 前言长、详细,反映作者对该领域的 Elena Gordo. George Z Chen. J. Fray" 了解和认识,增加论文的可信性; 帮助读者了解背景,加深印象。 1. Introduction charge(mixed powders of Cr2 O3 and Al)melts in a couple of minutes after ignition by means of, e. g. mixture of barium Invented by Hans Goldschmidt in 1898. the Goldschmidt peroxide and fine Al powder [1]. The heat released from process is at present the dominant production technique this reaction is so high that the chromium is in the liquid used in the chromium metal industry [1-3]. In this process, state, in spite of its high melting point of 1857C. Similarly, chromium oxide( Cr2O3) powder, which is prepared from the chromium oxide(Cr2O3) may also be reduced by Si or C mineral ore, FeCr2O4(FeOCr2 O3), is reduced to chromium and the products include Cr metal, SiO2 or Co [1]. The metal via the following reaction main problem of the Goldschmidt process is the contamina- Cr?03+2Al- 2Cr(1)+Al O3 (1) tion of the product by the unreacted reductant, particularly aluminium which forms both alloy and intermetallic com- Reaction(1). also termed as aluminothermic reduction, pounds with chromium [4. In addition, because aluminium has very negative values of AH and AG(at 1000C, is produced by electrolysis. the use of aluminium as the. 521.92 and-44645kJ, respectively), and is hence highly reductant makes the Goldschmidt process more expensive exothermic(no need for external heating), and spontaneous than an electrolytic method if the current efficiency can be (self-propagating). Indeed, in the industrial practice. a ton of comparable to or higher than that of aluminium production 简介铬的主要工业生产方法“HG方 指出“HG方法”的产品缺点-杂质。 法”及其特点-高放热、自发反应。 指出“HG方法”的过程缺点-多步
正文：前言(例4) B类全论文前言 简介铬的主要工业生产方法“HG方 法”及其特点---高放热、自发反应。 指出“HG方法”的产品缺点---杂质。 指出“HG方法”的过程缺点---多步。 前言长、详细，反映作者对该领域的 了解和认识，增加论文的可信性； 帮助读者了解背景，加深印象
正文:前言(例4) Table 1 Electrode reactions in the aqueous solution of NH4 Cr(SO4)2 [2] B类全论文前言 Electrodes Main reactions Side reactions anode Cr(山+e→Cr() Claiming a purer product, electrolysis, or more accurately Cr(I)+2e→Cr(s) Cr(+3e→Cr(I) electrochemical deposition of chromium from an electrolyte Anode is also widely used for chromium metal production. The cur 2H2O→O2(g)+4H++4eCr(→Cr(I+3e2 rent industrial method uses an aqueous electrolyte [2.Be- Cr(In is formed at the cathode but not transported to the anode cause most simple compounds of chromium are either un- because it is unstable in water stable in air(e.g. CrCl2)or insoluble in water(e.g. CrCl3). the electrolytic process is carried out in an aqueous solu electrolysis can be expressed by the reaction below tion of NH, Cr(IIr(SO4)2 which is prepared by dissolving the cheap Fe2 Cr alloy in a type of chrome alum contain 4NH4 Cr(SO4)2+6H2O ing H2SO4+(NH4)2 SO4 [2]. The overall chemistry of the →4Cr+2(NH4)2SO4+6H2SO4+302(9) However, the relevant electrochemistry is much more com- plex as shown in Table I which lists the main and side elec- 简介铬的另一种工业生产方法“水溶 trode reactions taking place during the electrolytic process. 液电沉积方法”及其特点-产品纯、 The side reactions, i.e. H2 gas evolution and the redox cy- cling of the multi-valent chromium ions between anode and 粉末。 cathode, are the main challenge to the electrolytic process 指出“电沉积方法”的过程缺点-低效 in aqueous solutions and account for the low current effi- 率导致的高能耗。 ciency and high energy consumption which are, respectively, about 45% and 18.5kWhkg Cr, even when a diaphragm is used
正文：前言(例4) B类全论文前言 简介铬的另一种工业生产方法“水溶 液电沉积方法”及其特点---产品纯、 粉末。 指出“电沉积方法”的过程缺点---低效 率导致的高能耗