【正文】 第一篇：過程裝備與控制工程專業(yè)英語翻譯10Reading Material 10Corrosion ControlCorrosion problems can be solved in the following ways:(1)Select a material that is resistant to be the corrosion environment.(2)Give metal a protective coating.(3)Change the service conditions, such as temperature, pressure, or velocity.(4)Change the environment chemistry such as pH, concentration, aeration, or impurities.(5)Add a corrosion inhibitor.(6)Shift the electric potential of the metal by cathodic or anodic protection(7)Modify the design of the equipment or system.(8)Let it corrode and replace it(often a viablealternative!)Once the engineer has determined that there is no danger of a catastrophe, deciding which way to bat corrosion usually es down to the economics of the SelectionStainless steels are usually the first choice for a “probably corrosive” environment with unknown properties, because these alloys are resistant to a wide range of oxidizers, but they cannot withstand strong reducing solutions, such as hydrochloric steels can be corroded, despite their stainless steels are classified into five general groups(martensitic, ferritic, austenitic, duplex and precipitationhardenable strainless steels)according to their metallurgical structures, with the of which one to use depending not only on corrosion resistance but also on required strength and pure nickel has high corrosion resistance, especially to alkalies, bined with mechanical properties similar to mild steel, and good and nickel alloys widely used in the food industry and are frequently selected for service in chlorine, hydrogen chloride, and chlorinated are very resistant to hightemperature air and to stresscorrosion is a very reactive metal in the standard electromotive force series。it immediately reacts with air to form a passive film consisting of two layers: an inner, pact, amorphous oxide and an outer, thicker, more permeable hydrated is naturally patible with the atmosphere and withstands many solutions well if the pH lies between about 4 to acids and moderately strong bases destroy aluminum’s passive ions are particularly damaging because they attack the film only at weak spots and pit chlorinated organic solvents and alcohols can attack aluminum alloys disastrously, sometimes CoatingsThe major purpose of coating a metal is to protect it from a corrosive environment when the metal is otherwise suitable for the service conditions in terms of mechanical and physical metal with good mechanical properties(usually steel)is often more practical in terms of cost and required life than selecting a more corrosion resistion but expensive can be achieved in four ways, with many coatings functioning in more than one way:(1)A barrier coating that prevents the corrosive environment from contacting the metal.(2)A sacrificial coating that corrodes while giving cathodic protection to the underlying metal.(3)An inhibitor coating that slows electrode reactions.(4)An electrically resistive coating that stifles electrochemical corrosion cells, Paints fall into this last InhibitorsAn inhibitor is a chemical added to the corrosive environment in small amounts to reduce the corrosion inhibitors interfere with the anode reaction, some with the cathode reaction, and some with usually used to prevent general corrosion but most are not effective in preventing localized attack, such as crevice corrosion, pitting, or stresscorrosion have a critical concentration that must be reached or exceeded for them to be effective, and in some cases to prevent them from making corrosion and Anodic ProtectionCathodic protection converts all anodic on a metal surface to cathodes so that corrosion protected metal has positive current flowing onto it from the electrolyte everywhere on the surface so that no current flows result can be achieved in two distinictly different ways.(1)By connecting a sacrificial anode the metal that is be protected.(2)By applying an electric current from a separate source, a technique called impressedcurrent cathodic protection, on the contray, makes the entire metal surface anodicso anodic that the metal pletely , then, this technique is limited to metals that can form protective passive passivated metals still corrode at a low rate, anodic protection almost, but not pletely, stops corrosion problems originate with either improper design or improper material , a good choice of material can overe severe environmental conditions and even some deficiencies in methods listed above are the accepted ways of dealing with a corrosion problem, but not all of them apply in a given particular, the corrosion engineer often cannot change the service conditions or environment may be as unalterable as the ocean, or nearly as unalterable: an industrial process that is running fairly smoothly where any change will be fanatically opposed by the production 腐蝕控制腐蝕問題的解決方法如下：（1）選擇抗腐蝕環(huán)境的材料；（2）給金屬加一個(gè)保護(hù)層；（3）改變工作條件，如溫度，壓力或速度；（4）改變化學(xué)環(huán)境，如PH值，濃度，通風(fēng)，雜質(zhì)；（5）添加緩蝕劑；（6）改變金屬陽極或陰極保護(hù)的電勢；（7）完善設(shè)備或系統(tǒng)的設(shè)計(jì)；（8）讓其腐蝕后取代它（通常是一個(gè)可行的替換物）。上面所列的方法來處理腐蝕問題是可行的，但是不是所有的都能應(yīng)用于一個(gè)給定的情況。特別是，腐蝕工程師常常不能改變操作條件或者化學(xué)環(huán)境。這就像在海洋上不能改變一樣或者是基本不能改變。一個(gè)運(yùn)行相當(dāng)平穩(wěn)的工業(yè)過程，其中任何改變都將遭到生產(chǎn)人員的強(qiáng)烈反對。大多數(shù)的腐蝕問題是由不正當(dāng)?shù)脑O(shè)計(jì)或不正當(dāng)?shù)牟牧线x擇引起的。然而，材料的優(yōu)良選擇可以克服一些惡劣的環(huán)境條件甚至是一些設(shè)計(jì)上的缺陷。工程師一旦確定沒有安全隱患，抗腐蝕的方法就轉(zhuǎn)移到經(jīng)濟(jì)形勢上了。材料的選擇不銹鋼通常作為一個(gè)具有未知性質(zhì)、“可能腐蝕”環(huán)境的首選材料，因?yàn)檫@些合金可以抵抗大范圍的氧化劑，但它們不能承受強(qiáng)還原性的溶液，例如鹽酸溶液。不銹鋼可以被腐蝕盡管它們的名字是那樣說的。根據(jù)合金結(jié)構(gòu)不銹鋼被分為五大類（馬氏體，鐵素體，奧氏體，雙鏈體和析出可硬化不銹鋼）。選擇哪一種鋼不僅要根據(jù)它的耐腐蝕性，而且要根據(jù)其所需的強(qiáng)度和成本。商業(yè)上的純鎳具有很強(qiáng)的耐腐蝕性，尤其是對堿金屬，結(jié)合與低碳鋼相似的機(jī)械性能和良好的焊接性。鎳和鎳合金廣泛運(yùn)用于食品工業(yè)，經(jīng)常使用于制氯業(yè)氣，氯化氫，氯化碳?xì)浠衔?。它們對高溫氣體應(yīng)力腐蝕破裂有很強(qiáng)的抵抗性。鋁在標(biāo)準(zhǔn)的電動(dòng)壓系列下是一種很活潑的金屬，它可以立即跟空氣反應(yīng)形成由兩層物質(zhì)組成的鈍化膜：里面一層是緊密的非晶氧化薄膜，外面是更厚的可透性氫氧化物。鋁可以跟空氣兼容，可以防止很多ＰＨ值為４到９的溶液。強(qiáng)酸和適量強(qiáng)堿會破壞鋁的鈍化膜。尤其是氯離子破壞有微弱和凹坑的鋁的氧化膜。很多氯的有機(jī)溶劑和醇類嚴(yán)重?fù)p害鋁合金，有時(shí)甚至是爆破性的。防護(hù)涂料給材料加上涂層的目的是為了保護(hù)金屬在腐蝕性環(huán)境中不被破壞，除非金屬的機(jī)械性能和物理性能能符合工作條件。給機(jī)械性能好的金屬（通常是鋼）加保護(hù)涂層常比選擇一種耐腐蝕但昂貴的材料更符合實(shí)際和生活要求。保護(hù)可以通過四種方法獲得，很多涂層功能不僅僅是一種。（1）防滲涂層可以防止金屬與腐蝕環(huán)境接觸。（2）給底層金屬作陰極保護(hù)的涂層會被腐蝕掉。（3）使用抑制劑減緩電極反應(yīng)。（4）電阻涂層抑制電化學(xué)腐蝕單元，涂料落在這最后的范疇。緩蝕劑抑制劑是一種添加到腐蝕環(huán)境中的少量化學(xué)藥