技術(shù)交流

2.1 紅銹，一種均勻腐蝕的形式

   Rouging, a form of (uniform corrosion)

  腐蝕基本上可以稱為在一個部件表面不期望的、熱力學(xué)引導(dǎo)的化學(xué)變化（在這種情況下：由不銹鋼合金制成的）。

   Corrosion can basically be referred to as an undesired, thermodynamically induced, chemical alteration of the surface of a component (in this case: one made of a stainless steel alloy).

  在不銹鋼合金技術(shù)中，已知由各種不同的因素和機制產(chǎn)生的更大范圍的各種不同的局部和均勻的腐蝕效應(yīng)，對該組件有或多或少嚴(yán)重的后果。

    In stainless steel alloying technology, a wide range of different local and uniform corrosive effects, resulting from various different causes and mechanisms having more or less serious consequences for the component, is known.

  就不銹鋼表面的紅銹效應(yīng)來說，這種現(xiàn)象是由于60℃以上溫度的缺氧超純水、或超純蒸汽的影響，富含鉻氧化物鈍化層的巨大變化、嚴(yán)重?fù)p壞甚至改變。這些變化隨之會形成一個主要為氧化鐵的紅銹層，可以被部分擦除。上面描述的均勻腐蝕過程在相關(guān)的技術(shù)文獻(xiàn)中被稱為“紅銹”，這是指通?？梢员?/span>擦去的富含紅色（富含氧化亞鐵）物質(zhì)顆粒的一個術(shù)語。

    In the case of rouging effects on a stainless steel surface, the phenomenon is a massive alteration in, serious damage to, or even inversion of the chromium-oxide-rich passive layer due to the influence of oxygen-deficient ultrapure water at temperatures > 60 °C, or ultrapure steam. These changes then result in a predominantly iron oxide rouging layer, which can be partially wiped away. The uniform corrosion process described above is referred to as 'rouging' in the related technical literature, which is a term derived from the reddish (Feoxide-rich) material particles that can usually be wiped away.

  從技術(shù)上講，紅銹描述了長期暴露在熱、缺氧、去鹽水下在不銹鋼表面的典型的金黃色向紅褐色薄層/變色形成。

  Technically speaking, rouging describes the typical golden-yellow to reddish-brown formation of film/discolouration on stainless steel surfaces with long-term exposure to hot, oxygen-deficient, salt-free water.

  在高溫的清潔的蒸汽系統(tǒng)(T>100℃)中，甚至可以觀察到附著在表面的紅銹由深棕色到紫色膜的形式的過程。相關(guān)材料分析表明，在不銹鋼表面形成的紅銹膜主要由重金屬氧化物顆粒（如鐵、鉻、鎳等）組成，其中氧化鐵含量明顯占多數(shù)的。因此，可以肯定地假設(shè)，就它們的類型和與成分的關(guān)系而言，紅銹沉積物都是特定不銹鋼合金的腐蝕產(chǎn)物。

    In clean-steam systems with high temperatures (T > 100 °C), it is even possible to observe rouging effects in the form of dark brown to violet films that normally stubbornly adhere to the surface. Relevant material analyses have shown that the rouge film formed on the stainless steel surface is essentially composed of heavy metal oxide particles (e.g. iron, chromium, nickel, etc.), with the iron oxide content clearly being predominant. As a result, it is safe to assume that—both with regard to their type and their relation to the composition—rouging deposits are a corrosion product of the specific stainless steel alloy.

圖7：紅銹層的形成[1]、[2]（Formation of a rouge layer [1], [2]）

 因此，從熱力學(xué)的角度來看，整個紅銹過程背后的化學(xué)過程是不銹鋼材料或它的金屬原子的高級氧化狀態(tài)，直接在與介質(zhì)接觸的表面上，這種狀態(tài)遠(yuǎn)遠(yuǎn)超出了鈍化反應(yīng)。

      From a thermodynamic standpoint, the che- mical process behind the entire rouging process is thus an advanced state of oxidation of the stainless steel material, or of its metal atoms, directly on the surface that has come into contact with media, a state that goes well beyond a passivation reaction.

  結(jié)合缺氧純水或清潔蒸汽作為環(huán)境條件質(zhì)量為1.4301/1.4404/1.4435/1.4571等的奧氏體不銹鋼表面，在高工藝溫度（>60℃）對不銹鋼表面的形態(tài)結(jié)構(gòu)或自然再鈍化性能有明顯的負(fù)面影響（=鈍化層的自我再生條件）。

     In combination with pure, oxygen-deficient water or clean steam as environmental conditions for austenitic stainless steel surfaces in qualities of 1.4301/1.4404/1.4435/ 1.4571 etc., high process temperatures (> 60 °C) have clear negative effects on the morphological structure or natural repassivation property of stainless steel surfaces (= self-regeneration of the passive-layer conditions).

  除了水中的缺氧外，高達(dá)100C的高水溫也會導(dǎo)致水分子的額外分解（解離），并伴隨著H+和oH離子的形成。由于氫氧化鐵的形成量增加，這反過來又對鈍化層的穩(wěn)定性產(chǎn)生了負(fù)面的影響。與此同時，缺氧不僅導(dǎo)致去鈍化，而且阻止任何進(jìn)一步充分的再鈍化（=鉻的氧化），因此，去鈍化和再鈍化的動態(tài)平衡發(fā)生了關(guān)鍵的轉(zhuǎn)變，這種平衡明顯地向去鈍化傾斜。

     In addition to the oxygen depletion in the water, high water temperatures of up to 100 °C also cause an additional decompo- sition (dissociation) of water molecules accompanied by the formation of H+ and OH-ions. As a result of the increased formation of iron hydroxide, this in turn has a negative influence on the stability of the passive layer. At the same time, the oxygen deficiency causes not only a depassivation, but also prevents any further adequate repassivation (= oxidation of chromium), whereby a critical shift in the dynamic balance of deand repassivation occurs, with this balance clearly tipping towards depassivation.

圖8：水分子隨溫度升高的分解、藍(lán)色曲線：含氧量降低、綠色曲線：水分解增加（離子形成）[1]。

Decomposition of water molecules as temperature increases Blue curve: Decrease in oxygen content Green curve: Increase in water decomposition (formation of ions) [1].

 綜上所述，這導(dǎo)致鈍化層的有效性顯著降低，并隨著時間的推移，由于封閉的保護性氧化鉻層的系統(tǒng)性破壞/分解，最終形成主要成分為鐵氧化物的紅銹層。在此過程中，以鐵為主的基材的影響被放大。就可能性而言，這些變化本質(zhì)上等于最初局部和最終完全的去鈍化。

     Taken together, this leads to a noticeable reduction in the passive layer's effectiveness and, over time, ultimately to the formation of the predominately iron oxide rouging layer, due to the systematic breakdown/decomposition of the closed protective chromium oxide layer. In the process, the impact of the iron-dominated base material is magnified. In terms of potential, these changes essentially amount to an initially local and eventually complete depassivation.

  由于其鍵能，特別是在較高的溫度下，鐵顯示對游離氫氧化根離子（水的）表現(xiàn)出更高的親和力，這是溫度導(dǎo)致的水分解增加的結(jié)果。在活化的不銹鋼表面更多的氫氧化鐵形式是作為二價鐵和三價鐵氧化物的前驅(qū)。

     Due to its bonding energies, iron exhibits— particularly at higher temperatures—a higher affinity for the free hydroxide ions (of the water) that are present as a result of the temperature-induced increased decomposition of the water. More iron hydroxide forms on the activated stainless steel surface as a precursor of the iron(II) and iron(III) oxide.

  在熱力學(xué)引導(dǎo)的相反轉(zhuǎn)中，主要的鉻氧化物保護層，最初作為一個鈍化表面存在，被轉(zhuǎn)化為富含鐵氧化物的層。這種新的鐵氧化物層（=紅銹層）形成了一個覆蓋層，它有一個微孔的層狀結(jié)構(gòu)，這是典型的鋼銹表面。紅銹生產(chǎn)/形成背后的機制本質(zhì)上是一種均勻腐蝕。在許多情況下，紅銹的腐蝕產(chǎn)物與由于機理完全不同而造成的均勻腐蝕沒有區(qū)別。

    In a thermodynamically induced phase inversion, the predominantly chromium oxide protective layer, which was initially present as a passive surface, is converted into a layer rich in iron oxide. This new iron oxide layer (= rouging layer) forms a cover which has a microporous, layered structure that is typical of rusty steel surfaces. The mechanism behind the production/formation of rouging is essentially a form of uniform corrosion. In many cases, no distinction can be made between the corrosion products of rouging and the uniform corrosion due to completely different mechanisms.

  與其他類型的腐蝕相比，典型的紅銹相對容易識別，通常是通過簡單的拭子檢測（見圖9）。

     Compared to other types of corrosion, typical rouging is relatively easy to identify, usually by means of a simple swab test (see Figure 9).

圖9：紅銹[6]覆蓋的不銹鋼表面的拭子樣品（Swab sample from a stainless steel surface covered by rouging [6]）

在許多應(yīng)用情況下，特別是在蒸汽滅菌器中，由于部件表面出現(xiàn)典型的紅銹膜由于水或水蒸氣溫度高缺氧和特定材料自身性能（=明確是不銹鋼合金）（熱力學(xué)）性能的相結(jié)合，無法避免伴隨的顯著變色。

      In many application cases—especially in steam sterilizers—the occurrence of typical rouging films on the component surface, and the accompanying significant discolouration, cannot be avoided due to the combination of high water or water vapour temperatures, oxygen deficiency and the (thermodynamic) property of the specific material (= defined stainless steel alloy).

  根據(jù)這些情況，運行人員需要指定預(yù)防和修復(fù)措施，以創(chuàng)造耐腐蝕的鈍化表面環(huán)境。

      In light of these circumstances, operators need to specify preventative and restorative measures in order to create corrosion-resistant passive surface conditions.

來自：德國的錢伯斯工作組(德語縮寫：AKK)的手冊