201044947 四、指定代表圖： (一）本案指定代表圖為：第（1 )圖。 (二)本代表圖之元件符號簡單說明： 殼體 10 金屬基體 11 底漆層 13 鉻或不銹鋼層 14 混鍍層 15 不鏽鋼層 16 面漆層 17 Ο 五、 本案若有化學式時，請揭示最能顯示發明特徵之化 學式： 益 六、 發明說明： 【發明所屬之技術領域】 ^ 本發明係關於一種殼體的製作方法，尤其係關於一種 〇 具有不銹鋼鍍膜層的殼體的製作方法及由該方法製得的殼 體。 【先前技術】 鎂及鎂合金由於其密度小、比強度高、比剛度大、減 震性能好，以及具有良好的電磁遮罩作用及很高的抗電磁 干擾能力等優點，在國防軍工、交通運輸、光學儀器及電 子裝置殼體等領域均有廣泛的應用。但同時鎂及鎂合金由 於電極電勢低，化學活性高等特點，其非常容易發生電化 201044947 學腐#，财腐餘性很差。這嚴重阻礙了鎮及鎮合金的應用。 為了克服上述缺陷，通常需要對鎂及鎂合金進行表面處 理，以在其表面生成一耐腐蝕、耐磨且具有裝飾效果的鍍 * 層0 真空鍍膜係一種在鎂或鎂合金殼體表面形成耐腐蝕、 耐磨且具有裝飾效果的鍍層的常用方法，如利用真空鍍膜 在鎂或鎂合金殼體表面形成一不銹鋼膜層，以得到具有高 光澤度、高貴金屬質感的殼體。由於鎂或鎂合金材料的化 〇 學活潑性及内部結構的特殊性，其表面通常較粗糙，且難 以藉由拋光等方式使其表面平整，因此真空鍍膜前通常需 . 要在鎮或鎮合金殼體表面喷塗一底漆層，以增強鑛膜層與 鎂或鎂合金殼體的結合力。然而由於單一底漆層其本身的 厚度較小，表面平整度較低，因而對增強鍍膜層與鎂或鎂 合金殼體的結合力的貢獻有限。 【發明内容】 鑒於此，有必要提供一種殼體的製作方法，該方法可 〇 在鎂或鎂合金基體表面形成具有較強附著力、且外觀優良 的金屬鍍膜層。 另，還有必要提供一種由上述方法所製得的殼體。 一種殼體的製作方法，其包括如下步驟： (a) 、提供一金屬基體； (b) 、在該金屬基體上形成一底漆層； (c) 、在該底漆層上真空鍍覆一鉻或不銹鋼層； (d) 、在該鉻或不錄鋼層上真空艘覆一鉻及不銹鋼的混 鍍層； 3 201044947 (e)、在所述混鍍層上真空鍍覆一不銹鋼層。 一種由上述方法所製得的殼體，其包括一金屬基體， 在該金屬基體上依次鑛覆有底漆層、鉻或不繡鋼層、鉻及 ‘ 不銹鋼的混鍍層、以及不銹鋼層。 相較於習知技術，本發明殼體的製作方法藉由在金屬 基體上設置底漆層及鍍覆多層金屬層，以在所述殼體上形 成附著力強、膜層均勻、色澤良好的金屬鍍層，可大大提 升產品的外觀吸引力及附加價值。 〇 【實施方式】 本發明較佳實施方式的殼體的製作方法包括如下步 驟： 提供一金屬基體，該金屬基體的材料為鎂或鎂合金。 對該金屬基體進行前處理。所述前處理包括除污處理及化 學成膜處理。所述除污處理為對所述金屬基體進行酸诜， 以除去其表面的油污。所述化學成膜處理為將所述金屬基 體置於含磷酸或磷酸鹽的溶液中使金屬基體的表面形成一 〇 鈍化的保護膜。化學成膜處理後對所述金屬基體進行清洗 並乾燥。 在所述乾燥後的金屬基體上形成底漆層。該底漆層可 為一層，其可由紫外光固化漆喷塗於所述金囑基體表面形 成，該底漆層的厚度約為55-65μιη。所述底漆層亦可為兩 層，喷塗時，先使用聚氨酯漆在金屬基體上形成第一底漆 層，該第一底漆層的厚度約為35-40μηι。第一底漆層形成 後進行乾燥，然後使用紫外光固化漆在第一底漆層上喷塗 第二底漆層，該第二底漆層的厚度約為20-25μιη。所述底 201044947 漆層可為白色或無色，其表面平整，可增強後續鍍覆的金 屬層的光澤度及其與金屬基體的結合力。 在所述底漆層上鐘覆一鉻或不繡鋼層，該鉻或不錄鋼 * 層的厚度在45-55nm之間。鍍覆該鉻或不繡鋼層的工藝條 件為：採用多弧離子鍍的方法，鍍覆時電源功率設置為 55-60KW，工作氣體為氬氣，壓強為0.4-0.6Pa，在室溫（約 20°C )下鍍覆約30-60秒。該鉻或不銹鋼層的厚度均勻， 色澤良好，其與底漆層的結合力較強。 〇 在上一步驟中所形成的鉻或不繡鋼層上鍍覆一鉻及不 銹鋼的混鍍層。該混鑛層的厚度在180-220nm之間。所述 鉻在該混鐘層中的含量約為30%。鍵覆該混鍵層的工藝條 件為：採用多弧離子鍍的方法在電源功率為55-60KW的條 件下鍍鉻的同時，採用直流濺鍍的方法在電源功率為 15-18KW的條件下進行不銹鋼的鍍覆。該步驟中鍍覆用工 作氣體為氬氣，鍍覆壓強為〇.4-0.6Pa，在室溫（約20°C ) 下鍍覆約90-180秒。所述混鍍層的厚度均勻，色澤良好。 〇 該混鍍層與所述鉻或不銹鋼層的結合力較強。 在所述混鑛層上鍵覆一不錄鋼層。該不錄鋼層的厚度 在15-25nm之間。鍍覆該不銹鋼層的工藝條件為：採用直 流濺鍍的方法，鍍覆時電源功率設置為15-18KW，工作氣 體為氬氣，壓強設置為0.4-0.6Pa，在室溫（約20°C )下鍍 覆約15秒。該步驟中形成的不銹鋼層厚度均勻，色澤良 好，其與所述混鍍層的結合力較強。 在所述不銹鋼層上喷塗一透明面漆層，以提高所述殼 體的耐磨耗性能。所述面漆層為透明的聚氨酯漆層，其厚 201044947 度在20-25μιη之間。 可以理解，所述在不銹鋼層上喷塗面漆層的步驟可以 省略。 * 所述金屬基體的材料亦可為鋁、鋁合金或鋅合金等， 所述對金屬基體的前處理包括除污處理。 請參閱圖1所示，由本發明較佳實施方式殼體的製作 方法所製得的殼體10包括一金屬基體11及依次形成該金 屬基體11上的一底漆層13、一絡或不錄鋼層14、一絡及 〇 不銹鋼的混鍍層15、一不銹鋼層16、及一面漆層17。所 述金屬基體11的材料為鎖、鎂合金、銘、銘合金或鋅合金 等；所述底漆層13可為單一的紫外光固化漆層，亦可為以 聚氨酯漆形成的第一底漆層與以紫外光固化漆形成的第二 底漆層的結合；所述面漆層17為透明聚氨酯漆層。 一 可以理解，所述面漆層17可以省略。 本發明殼體的製作方法藉由在金屬基體上設置平整度 高的底漆層及鍍覆多層金屬層，並藉由控製適當的鍍膜參 〇 數、各金屬層的厚度、混鏟層中鉻與不銹鋼含量的比例等， 使得本發明殼體上形成的金屬鍍層附著力強、膜層均勻、 具有良好的不銹鋼色外觀，大大提升了產品的外觀吸引力 及附加價值。 【圖式簡單說明】 圖1為本發明一較佳實施方式殼體的剖面示意圖。 【主要元件符號說明】 殼體 10 金屬基體 11 底漆層 13 鉻或不銹鋼層 14 201044947 混鍍層 15 不鏽鋼層 面漆層 17201044947 IV. Designated representative map: (1) The representative representative of the case is: (1). (2) Brief description of the symbol of the representative figure: Shell 10 Metal base 11 Primer layer 13 Chromium or stainless steel layer 14 Mixed plating layer 15 Stainless steel layer 16 Topcoat layer 17 Ο 5. If there is a chemical formula in this case, please reveal the best TECHNICAL FIELD OF THE INVENTION The present invention relates to a method of fabricating a casing, and more particularly to a method for manufacturing a casing having a stainless steel coating layer and a method therefor. The resulting housing. [Prior Art] Magnesium and magnesium alloys are advantageous in defense industry and transportation because of their low density, high specific strength, high specific stiffness, good shock absorption performance, good electromagnetic shielding and high anti-electromagnetic interference capability. It is widely used in transportation, optical instruments and electronic device housings. At the same time, magnesium and magnesium alloys are characterized by low electrode potential and high chemical activity, which are very prone to electrification. This seriously hinders the application of towns and towns. In order to overcome the above defects, it is usually necessary to surface-treat magnesium and magnesium alloys to form a corrosion-resistant, wear-resistant and decorative coating on the surface of the coating. 0 Vacuum coating is a kind of resistance on the surface of magnesium or magnesium alloy casing. A common method of etching, abrasion-resistant, and decorative coatings, such as forming a stainless steel film layer on the surface of a magnesium or magnesium alloy casing by vacuum coating to obtain a casing having a high gloss and noble metal texture. Due to the chemistry and the speciality of the internal structure of magnesium or magnesium alloy materials, the surface is usually rough, and it is difficult to flatten the surface by polishing, etc. Therefore, it is usually required before vacuum coating. A primer layer is applied to the surface of the casing to enhance the bonding strength of the mineral film layer to the magnesium or magnesium alloy casing. However, since the single primer layer has a small thickness and a low surface flatness, the contribution of the reinforcing coating layer to the magnesium or magnesium alloy casing is limited. SUMMARY OF THE INVENTION In view of the above, it is necessary to provide a method of fabricating a casing which can form a metal plating layer having a strong adhesion and an excellent appearance on the surface of a magnesium or magnesium alloy substrate. In addition, it is also necessary to provide a casing produced by the above method. A method of manufacturing a casing, comprising the steps of: (a) providing a metal substrate; (b) forming a primer layer on the metal substrate; (c) vacuum plating a layer on the primer layer a layer of chrome or stainless steel; (d) a vacuum coating of a mixed layer of chromium and stainless steel on the chrome or non-recorded steel layer; 3 201044947 (e), vacuum plating a stainless steel layer on the mixed plating layer. A casing obtained by the above method, comprising a metal substrate on which a primer layer, a chromium or stainless steel layer, a chromium and a 'stainless steel mixed layer, and a stainless steel layer are sequentially coated. Compared with the prior art, the manufacturing method of the present invention is characterized in that a primer layer and a plurality of metal layers are plated on a metal substrate to form a strong adhesion, a uniform film layer and a good color on the casing. Metal plating can greatly enhance the attractiveness and added value of the product.实施 [Embodiment] The manufacturing method of the housing of the preferred embodiment of the present invention comprises the following steps: A metal substrate is provided, the material of which is magnesium or a magnesium alloy. The metal substrate is pretreated. The pretreatment includes a desmear treatment and a chemical film formation treatment. The desmutting treatment is to subject the metal substrate to acid hydration to remove oil stains on the surface thereof. The chemical film forming treatment is to place the metal substrate in a solution containing phosphoric acid or a phosphate to form a passivation protective film on the surface of the metal substrate. After the chemical film formation treatment, the metal substrate is washed and dried. A primer layer is formed on the dried metal substrate. The primer layer may be a layer which may be formed by spraying an ultraviolet curable lacquer onto the surface of the ruthenium substrate, the primer layer having a thickness of about 55-65 μm. The primer layer may also be two layers. When spraying, a first primer layer is formed on the metal substrate by using a polyurethane paint. The first primer layer has a thickness of about 35-40 μm. The first primer layer is formed and dried, and then a second primer layer is applied to the first primer layer using a UV-curable lacquer layer, the second primer layer having a thickness of about 20 to 25 μm. The bottom layer 201044947 may be white or colorless, and its surface is flat to enhance the gloss of the subsequently plated metal layer and its adhesion to the metal substrate. A layer of chrome or stainless steel is coated on the primer layer, and the thickness of the layer of chromium or non-recording steel is between 45 and 55 nm. The process conditions for plating the chrome or stainless steel layer are as follows: multi-arc ion plating method, the power supply power is set to 55-60 KW during plating, the working gas is argon gas, and the pressure is 0.4-0.6 Pa at room temperature ( It is plated at about 20 ° C for about 30-60 seconds. The chrome or stainless steel layer has a uniform thickness and good color, and has a strong bonding force with the primer layer.镀 A layer of chrome and stainless steel is plated on the chrome or stainless steel layer formed in the previous step. The mixed layer has a thickness between 180 and 220 nm. The chromium is present in the mixed layer in an amount of about 30%. The process conditions for bonding the mixed layer are: using a multi-arc ion plating method to chrome while the power source is 55-60 KW, and using a direct current sputtering method to perform stainless steel under the condition of a power of 15-18 KW. Plating. In this step, the working gas for plating is argon gas, the plating pressure is 〇.4-0.6 Pa, and plating is performed at room temperature (about 20 ° C) for about 90-180 seconds. The mixed plating layer has a uniform thickness and a good color. 〇 The mixed plating layer has strong bonding force with the chromium or stainless steel layer. A steel layer is not bonded on the mixed layer. The thickness of the unrecorded steel layer is between 15 and 25 nm. The process conditions for plating the stainless steel layer are: DC sputtering method, the power supply is set to 15-18KW when plating, the working gas is argon gas, the pressure is set to 0.4-0.6Pa, at room temperature (about 20 ° C ) plating for about 15 seconds. The stainless steel layer formed in this step has a uniform thickness and a good color, and has a strong binding force with the mixed plating layer. A transparent topcoat layer is sprayed onto the stainless steel layer to improve the wear resistance of the shell. The topcoat layer is a transparent polyurethane lacquer layer having a thickness of 201044947 between 20-25 μm. It will be understood that the step of spraying the topcoat layer on the stainless steel layer may be omitted. * The material of the metal substrate may also be aluminum, aluminum alloy or zinc alloy, etc., and the pretreatment of the metal substrate includes a desmutting treatment. Referring to FIG. 1 , a housing 10 prepared by a method for manufacturing a housing according to a preferred embodiment of the present invention includes a metal base 11 and a primer layer 13 formed on the metal base 11 in sequence. The steel layer 14, the mixed plating layer 15 of a collateral and bismuth stainless steel, a stainless steel layer 16, and a lacquer layer 17 are provided. The material of the metal substrate 11 is a lock, a magnesium alloy, an alloy, a zinc alloy, or the like; the primer layer 13 may be a single ultraviolet curing lacquer layer, or may be a first primer formed of a urethane lacquer. The layer is combined with a second primer layer formed of a UV curable lacquer layer; the topcoat layer 17 is a transparent polyurethane lacquer layer. It will be understood that the topcoat layer 17 can be omitted. The method for manufacturing the casing of the present invention comprises: setting a high-level primer layer on the metal substrate and plating the plurality of metal layers, and controlling the appropriate number of coatings, the thickness of each metal layer, and the chromium in the shovel layer. The ratio of the content of the stainless steel and the like makes the metal plating layer formed on the casing of the present invention have strong adhesion, uniform film layer and good appearance of stainless steel color, which greatly enhances the appearance appeal and added value of the product. BRIEF DESCRIPTION OF THE DRAWINGS Figure 1 is a schematic cross-sectional view of a housing in accordance with a preferred embodiment of the present invention. [Main component symbol description] Housing 10 Metal base 11 Primer layer 13 Chromium or stainless steel layer 14 201044947 Mixed coating 15 Stainless steel layer Topcoat layer 17