Name: Suzhou cycas Microelectronics Co., Ltd.
Address: 1st floor,B06 building,No.2,Fuxing Road,Zhangjiagang Economic Development Zone,Jiangsu Province 215600PRC
(1)比強度高。鈦合金具有很高的強度,其抗拉強度為686~1 176 MPa,而密度僅為鋼的60%左右,所以比強度很高。
17 世紀是一個醫藥化學和試驗酸、堿對各種不同材料影響的時代。約翰·格萊伯在這方麵取得了不少的進展，其中包括對鹽酸製造方法的改進。在這一時期化學腐蝕技術在未來航空工業上的應用也顯露出來。當時人們采用酸和鐵屑反應的方法來製取氫氣球進行升空。這就是說，在人們企圖飛行的Z初階段，已開始利用酸的腐蝕能力來幫助航空事業的發展。到 20 世紀 60 年代中期，由於蝕刻機加工及防蝕技術的發展，已經使蝕刻機加工成為一種非常有實用價值的生產加工方法，在航空航天工業中得到廣泛應有。
鈦合金蝕刻機加工液中 HF是超過其它任何酸的強蝕刻液。在室溫的 HF 溶液中，鈦就能被腐蝕，隨著酸濃度的增加，腐蝕速度明顯增大。
H2CrO4和 HNO3為蝕刻機加工液中常用的氧化劑，早期鈦的蝕刻機加工，在美國廣泛采用的蝕刻液是以 HF 和 H2CrO4為基礎的混酸型蝕刻機加工液，隨後英國人采用 HF 和 HNO3為基礎的混酸型蝕刻機加工液。但 H2CrO4成本高、對環境的汙染嚴重、反應後試樣易氫脆;而 HNO3作為強氧化劑，有強烈的氧化性，使氫氣隨即被氧化成水，抑製了吸氫反應，使鈦表麵吸附的氫減少。
① 反應過程中是否可以減少試樣表麵的吸氫量，防止氫脆; ② 對試樣加工前後各項力學性能無任何影響; ③ 試樣腐蝕溶解速度均勻，提高試樣表麵質量;
④ 不影響蝕刻機加工液各成分發揮效用，使蝕刻機加工液壽命延長。 四、蝕刻機加工的優點和局限性： 蝕刻機加工具有諸多優點，對於某些用機械方法難於加工的零件確實有其獨到之處：
③ 加工過程中無機械力，無加工應力，對工件幾乎無剛度要求; ④ 蝕刻機加工時工裝設備簡單、價廉;
⑤ 能加工沿著整個長度方向上截麵均勻變化的，長而薄的錐形工件; ⑥ 蝕刻機加工能不間斷的進行工件加工且能很快加工出想要的各種形狀。 但蝕刻機加工也不是一種萬能的加工方法，它也會受到很多因素的限製。其中Z主要的限製為：
d. 蝕刻機加工過程中各種酸液揮發，易造成環境汙染，影響人身健康。 五、鈦合金精密蝕刻機加工：
② 零件尺寸大小的影響： 不同於小型零件的蝕刻機加工，對於一個大型的板材零件如果是垂直放於腐蝕槽中，經腐蝕後由於蝕刻機加工速度的不同會出現下薄上厚的錐形，所以在計算公差時也應把這種由於蝕刻機加工本身造成的公差計入總公差。對於小型零件這種現象可以忽略不計。
1、 Overview of titanium and titanium alloy:
The abundance of Ti in the earth's crust is 0.56% (mass fraction, the same below), ranking 9th in all elements, and 4th in metals that can be used as structural materials, next to Al, Fe, Mg. Its reserves are more than the sum of common metals Cu, Pb, Zn. China is rich in titanium resources, with the largest reserves in the world. Titanium alloy is a new type of structural material with great development potential and application prospect because of its low density, high specific strength, high specific stiffness, good corrosion resistance, high temperature mechanical properties, fatigue resistance and creep resistance. In recent years, the world titanium industry and titanium material processing technology have been developed rapidly. The production and consumption of sponge titanium, deformed titanium alloy and titanium alloy processing materials have reached a very high level. They are widely used in the field of aerospace, naval ships, weapons and other military products manufacturing. They also have great application potential in automobiles, chemistry, energy and other industries.
Since 2001, titanium has been used more widely, and its application in some emerging markets, such as automobiless, oil and natural gas, has increased. In the long run, the amount of titanium used in automobiless will continue to increase and become a more secure competitive field for titanium applications. The application of titanium alloy in the field of high-end consumer goods has also been basically mature, such as the application of titanium alloy in golf clubs and tennis rackets. Nowadays, the aging problem is becoming more and more serious. The demand for titanium in the pharmaceutical market is increasing at a rate of 5% - 7% every year. Titanium in the biomedical sector has become another hot and broad application prospect. The consumption of titanium in the above emerging markets is increasing every year. In 2001, the consumption of titanium was 6000 tons, and in 2006, it increased to 10000 tons. After 2007, with the development of economy and the need of national defense, the demand for titanium alloy products in the international market has greatly increased, especially in the field of aerospace, which will become the main consumption and application field in the international market in the next few years.
Titanium and its alloys have many excellent properties, mainly in the following aspects:
(1) high specific strength. Titanium alloy has very high strength, its tensile strength is 686 ~ 1176mpa, and its density is only about 60% of steel, so its specific strength is very high.
(2) High hardness. The hardness HRC of titanium alloy (as annealed) is 32-38.
(3) Low modulus of elasticity. The elastic modulus of titanium alloy (annealed) is 1.078 @ 105 ~ 1.176 @ 105Mpa, about half of that of steel and stainless steel.
(4) High and low temperature performance. At high temperature, titanium alloy can still maintain good mechanical properties, its heat resistance is far higher than aluminum alloy, and the working temperature range is wide. At present, the working temperature of the new heat-resistant titanium alloy can reach 550-600e; at low temperature, the strength of titanium alloy is higher than that at normal temperature, and it has good toughness. At - 253e, the low temperature titanium alloy can still maintain good toughness.
(5) Titanium has strong corrosion resistance. When titanium is in the air below 550E, a thin and compact titanium oxide film will be formed on the surface of titanium rapidly. Therefore, in the oxidizing media such as atmosphere, sea water, nitric acid and sulfuric acid and strong alkali, its corrosion resistance is better than that of most stainless steels.
2、 Research progress of plasma etching machining of titanium alloy:
As a chemical cutting technology, etching machining has a long history. In Europe, chemical etching became popular in the 15th century, when it was mainly used for the processing of armor and the etching of artwork. The earliest European writing recorded that all the etchant formulations were made of salt, activated carbon and vinegar. The earliest anti-corrosion material recorded is flax oil coating as the protective layer, and later some records also use paraffin as the anti-corrosion agent.
The 17th century is an era of medicinal chemistry and the experiment of the influence of acid and alkali on various materials. John Graber has made a lot of progress in this field, including the improvement of hydrochloric acid manufacturing method. In this period, the application of chemical corrosion technology in the future aviation industry is also revealed. At that time, people used acid and iron chips to react to make hydrogen balloons for launching. That is to say, in the initial stage of people's attempt to fly, acid corrosion ability has been used to help the development of aviation industry. By the mid-1960s, due to the development of etching and anti-corrosion technology, etching has become a very practical production and processing method, which is widely used in aerospace industry.
Compared with other technologies, etching machining technology can make many parts more simple, easier and cheaper to produce, which provides a method that is difficult to realize for machining some parts. At the same time, as a kind of precise and scientific chemical processing technology, etch machining is widely used to corrode a variety of different graphics and shapes on a variety of metal materials. In recent decades, with the development of economy and the need of national defense, people pay more and more attention to the application of etching machining technology. For example, the development of tourist souvenirs, the production of nameplates, medals, coding plates and display electrodes, printing rollers and templates, fine parts, etc., are all inseparable from the etching machining technology.
3、 Formula of chemical etching machining fluid for titanium alloy:
The etching machining fluid for titanium alloy mainly contains etching fluid, oxidant and additive:
(1) HF in etching machining fluid for titanium alloy is stronger than any other acid. In HF solution at room temperature, titanium can be corroded. With the increase of acid concentration, the corrosion rate increases obviously.
(2) The oxidants H2CrO4 and HNO3 are commonly used in the etching machining fluid. In the early stage of titanium etching machining, the etching fluid widely used in the United States was a mixed acid etching machining fluid based on HF and H2CrO4. Later, the British adopted the mixed acid etching machining fluid based on HF and HNO3. However, the cost of H2CrO4 is high, the pollution to the environment is serious, and the sample is easy to hydrogen embrittlement after reaction. As a strong oxidant, HNO3 has strong oxidability, which immediately oxidizes hydrogen to water, inhibits the hydrogen absorption reaction, and reduces the hydrogen adsorbed on the titanium surface.
(3) Additives Additives have the function of improving the surface quality of the sample. During the etching and machining of titanium alloy, defects such as air groove, erosion groove, corrugation, ridge and pockmarks should be prevented. At the same time, hydrogen absorption should be reduced to prevent hydrogen embrittlement of the material. Excellent surfactants should have many functions such as reducing surface tension and wetting. It is difficult for an additive to have these functions at the same time Therefore, it is necessary to add several additives at the same time to achieve the requirements of etching accuracy without affecting the mechanical properties of materials. The following aspects should be considered in the selection of additives for titanium alloy etching machining:
① in the reaction process, whether the hydrogen absorption on the sample surface can be reduced to prevent hydrogen embrittlement;
② there is no effect on the mechanical properties of the sample before and after processing;
③ the corrosion dissolution speed of the sample is uniform to improve the surface quality of the sample;
④ It does not affect the effectiveness of the components of the etching fluid, so as to prolong the service life of the etching fluid. 4、 Advantages and limitations of etch machining:
Etch machining has many advantages, for some parts that are difficult to be machined by mechanical methods, it has its own unique features:
① it can process metal materials with high hardness and toughness;
② it can process workpieces with complex shapes, such as single hyperbolic thin-walled workpieces, etc;
③ In the process of machining, there is no mechanical force, no machining stress, and there is almost no rigidity requirement for the workpiece;
④ the tooling equipment is simple and cheap during etching machining;
⑤ the long and thin tapered workpiece with uniform section change along the whole length direction can be processed;
⑥ the etching machining can continuously process the workpiece and quickly process the desired shapes. But etching machining is not a universal processing method, it will also be limited by many factors. The most important limitation is:
a. the etching machining can only be based on the original surface state of the parts, and the progressive cutting. Therefore, the shape and surface quality of parts machined by etching are directly related to the original shape and surface quality of parts. More often, the etched machined surface is completely parallel to the original initial reference surface. From these limitations, it can be seen that etching machining can not use rough surface plates, bars and other parts to process complex shapes;
b. Etching machining cannot be used to process narrow and deep grooves, because the bubbles generated in the process of etching machining reaction will gather under the edge of the anti-corrosion layer. These bubbles blocked under the anti-corrosion layer will separate the metal surface from the etching solution, resulting in a very irregular corrosion, forming a very irregular edge, which is very unfavorable for the processing of deep parts;
c. It can't be drilled by etching machining. Etching machining drilling is different from mechanical drilling and electrolytic drilling. It can't process the hole shape that the latter two can process. Choosing appropriate technology can drill holes with flat wall, while etching machining can only drill holes with irregular cone shape. Because of the long time of corrosion, the tolerance of deep etching machining drilling increases, so the etching machining drilling is generally not used;
d. in the process of etching machining, all kinds of acid volatilization is easy to cause environmental pollution and affect personal health.
5、 Precision etching machining of titanium alloy: the dimensional accuracy of etching machining is affected by two aspects:
a. the deviation of etching machining itself in the process of machining is caused by the different corrosion speed on each machined surface, which makes the thickness or corrosion depth of metal removed by corrosion different.
b. The accuracy of the corroded material refers to the deviation existing in the raw material itself before the chemical corrosion of the parts, also known as the rough embryo deviation. The tolerance in the etching machining is the sum of these two precision deviations, so both deviations must be calculated in the etching machining, otherwise the parts processed by the etching machining will have a large degree of dimensional deviation. The machining tolerance of etching machining is mainly affected by the following factors:
① Influence of material composition of parts: the same etching fluid has different etching machining speed and side etching rate for different materials, so that different materials can get different surface precision after corrosion. However, even if the same material may have different corrosion rate and effect due to different material model and batch, different corrosion tolerance will be produced in the same corrosive solution.
② Influence of part size: different from the etching machining of small parts, if a large plate part is placed vertically in the corrosion groove, there will be a taper with thin bottom and thick top due to different etching machining speed after corrosion, so the tolerance caused by the etching machining itself should also be included in the total tolerance when calculating the tolerance. This phenomenon can be ignored for small parts.
③ Effect of etch machining depth: There is a direct relationship between the etching depth and the immersion time of the parts in the etching solution. The deeper the etching depth is, the longer the parts are immersed in the etching solution, and the corrosion dissolution reaction takes place in the etching solution, in which the composition and concentration of various chemical components change more and more, thus increasing the etching processing speed and corrosion effect. At the same time, when the depth reaches a certain value, due to concentration polarization and corrosion residue deposition, the corrosion dissolution behavior and mechanism behavior will also change.
④ Effect of etching solution: due to the difference of the main composition and concentration of etching solution, it has a certain impact on the etching speed and surface quality of parts. With the change of the concentration of etching solution and oxidant in the solution, the machining speed of etching will also change, which will have a certain impact on the surface quality of parts, and then affect the change of the total tolerance of parts.
6、 Effect of etching machining on mechanical properties of materials: after etching machining, the original mechanical properties of metals will be affected to some extent, which will increase with the increase of corrosion degree.