外文翻譯---碳結(jié)構(gòu)和固體顆粒侵蝕的保護高度多孔炭碳復(fù)合保溫材料的使用-材料科學-文庫吧在線文庫
【正文】 76。 of particular interest is their relationship between the erosion rate and the angle of incidence [15]. Ductile materials tend to display maximum erosion at glancing angles of impact, approximately 30176。, 45176。 500 lm。 的發(fā)生率 。 由于高孔隙度和纖維取向、導(dǎo)熱系數(shù)垂直于纖維層 比較 低 ,一個典型的 有用 的材料有 表面 密度 ℃ 的真空中 2020℃。 特別有趣的是 他們之間關(guān)系的侵蝕率和入射角 。 此外 ,一個高密度碳復(fù)合材料由使用 CVD 在一段 800 h 滲透到 5 毫米厚的部分CBCF 襯底一個密度的 3 m/mg。隨后的材料熱處理 900176。文丘里安裝在系統(tǒng)允許粒子傳遞壓縮空氣中流動。侵蝕試驗 角度 在 30176。當計算其腐蝕率、大規(guī)模的從滲透 時， 必須被考慮的 。纖維的方向是顯而易見的顯微纖維 ， 優(yōu)先在 x y 平面 (即垂直于 z 方向 )但方向隨意在這些 空間運用 。大型塊狀 的碳 (500lm)被發(fā)現(xiàn)的 各 層 之 間 ,可以看到在該計劃部分微型圖。碳顆粒較粗的增加的粘度涂料 ,結(jié)果在一個 較厚的表面涂層 (80200 lm)， 通過最小化的程度滲透多孔基體的內(nèi)部 。掃描電鏡樣品 ,安裝在選項卡并檢查了鋁在加速電壓 20 千伏。 通常 ,這些樣品是一個固定的 角度控制 質(zhì)量 的 ,然后 再 清洗和 再 稱重 。從篩的是粒子大小在 150nm 到 300nm 之間、平均大小 (重量 )是 230mg/m。 石墨具有 靈活的性質(zhì)的 ,主要是由機械鎖在一起 ,因為沒有使用 額度的話 。 2 實驗過程 這個 CBCF 用作基體上標準的商業(yè)材料 (密度 ),公司生產(chǎn)的涂層和熔覆材料 ,應(yīng)用在 x y 平面上的 CBCF 基質(zhì) 。 本文關(guān)注的是 測定 的顯微組織及 有效 改善耐蝕性的幾個 備用 涂料和推 。 天然氣的優(yōu)勢淬火熱處理中 ， 相對于一個油淬火 ,冷卻速度是可以控制的 ；因此， 它有可能減少對變形和開裂的組件 。C 。 涂層和熔覆材料顯示一個更大的抗侵蝕對所有 角度的發(fā)病率比多孔碳復(fù)合材料。. Generally, the samples were impacted by a fixed mass of erodent, then cleaned and reweighed. This process was repeated and the accumulated mass loss plotted against the accumulated mass of erodent. The erosion rate, expressed in terms of mass removed perunit mass of erodent, was calculated from the gradient of these plots. However, in the case of the lowdensity CBCF substrate material, which was investigated for parison purposes, a significant mass of erodent perated and was retained within the porous structure of the posite. When calculating the erosion rate, the mass of this perated erodent must be taken into account and therefore the erosion rate was found in the following manner. Each sample received only a single dose of erodent. The total mass change of each sample, *188。C in nitrogen to carbonize the resin constituent of the colloid. Higher density carbon— carbon posites (39。C. A consequence of the vacuummoulding process used in the production of the posite is that the discontinuous fibres are orientated into layers to form a twodimensional planar random structure. The vast majority of the volume of the posite consists of interconnected pores and the fibre work is bonded at the intersections of fibres by discrete regions of the carbon matrix as opposed to a continuous matrix. For this reason these posites are also known as carbon bonded carbon fibre (CBCF). As a result of the high porosity and the fibre orientation,the thermal conductivity perpendicular to the fibre layer planes is low, a typical value for a material with a nominal density of Mg m\3 is W m\1 K\1 at 2020 176。C in vacuum . Investigations into the microstructure [3, 4], mechanical properties [2, 5— 9] and thermal properties [10, 11] of these materials have been reported. ( 1997 Chapman amp。 Mg m\3) used as cladding pressure of 5 kPa. (Note that the CVD of carbon in the interior of a porous medium is sometimes termed chemical vapour infiltration, CVI.) Another cladding material was graphite foil which was produced by Toyo Tanso by pressing exfoliated graphite ?akes in a rolling operation [23]. The foil is ?exible in nature and is predominantly held together by mechanical locking, as no binder is
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