201143970 六、發明說明： 【發明所屬之技術領域] 本發明係關於鎂合金板的表面加工方法、及藉由該表 面加工方法所製造的鎂合金板。特別是關於在硏磨鎂合金 板使表面平滑之情況，在該鎂合金板的表面，污漬、著色 等不顯眼之表面加工方法、及藉由該表面加工所製造的鎂 合金板。 【先前技術】 近年’鎂（以下稱爲Mg)合金板逐漸被利用於手機、 筆記型電腦等的筐體等。例如，在專利文獻1，記載有在 後製程，能夠對Mg合金板均等地實施細微的凹凸加工，而 作爲Mg合金的輥軋材實施作爲予備加工之硏磨加工之內容 。作爲該硏磨加工的代表例，可舉出濕式皮帶式硏磨。 〔專利文獻1〕日本特開2009- 1 20877號公報 【發明內容】 〔發明所欲解決之課題〕 近年，具有更高金屬質感之Mg合金板需要。因應這樣 的需求，針對前述硏磨加工的條件進行試驗。其結果得知 ，當將Mg合金板的表面濕式硏磨加工成更平滑時’則會有 在Mg合金板表面污漬、著色等顯眼之情況’這些污漬、著 色等之存在可能成爲對Mg合金板的金屬質感的提升之阻礙 原因。 -5- 201143970 本發明係有限於前述事情而開發完成之發明，其一目 的係在於提供在將Mg合金板的表面濕式硏磨成平滑之情況 ，能夠使合金板表面的污漬、著色等不顯眼之Mg合金板的 表面加工方法。 本發明的另一目的係在於提供藉由前述本發明的表面 加工方法所製造的Mg合金板.。 〔用以解決課題之手段〕 本發明者們，針對在Mg合金板的表面所產生之污漬、 著色等的原因進行精心檢討。其結果，獲得下述見解。 (1 )若將Mg合金板表面進行濕式硏磨，則Mg合金板 的表面會被切削，而產生新生面，該新生面暴露於硏磨液 、洗淨液，造成腐蝕，該腐蝕會成爲污漬、著色等之一原 因。 (2)此污漬、著色等，若Mg合金板的表面粗，則比 較不顯眼，但，越將同表面的平滑性提高，則變得越顯眼 (3 )即使硏磨液、洗淨液等與新生面之接觸時間極 短，前述腐蝕也一樣行進。 本發明係依據前述見解而開發完成的發明，其藉由減 少Mg合金板與濕式硏磨過程中所使用之液體的接觸時間， 來達到前述目的。 本發明的Mg合金板的表面加工方法係具有：硏磨製程 :洗淨製程；除水製程；及乾燥製程。在硏磨製程，在使 -6- 201143970 用硏磨液之狀態下，藉由硏磨材，將搬送之Mg合金板的表 面進行硏磨。在洗淨製程，進行硏磨製程後，以洗淨液沖 洗附著於Mg合金板上之硏磨液。在除水製程，進行洗淨製 程後，將附著於Mg合金板之洗淨液予以除去。在乾燥製程 ，將除水製程無法完全除去而殘存於Mg合金板的表面之洗 淨液予以乾燥。且在硏磨製程，其目的係在於使Mg合金板 的表面粗糙度符合算術平均粗糙度RaS 1.2 μπι、最大高度 RmaxS20pm、及十點平均高度Rz$12pm中的至少一者。 又，前述硏磨、洗淨、除水、乾燥的各製程係在線內進行 〇 若依據前述結構，藉由在洗淨製程後具有除水製程， 能夠除去在洗淨製程所使用之洗淨液。因此，因洗淨液附 著於Mg合金板的表面之時間變短，所以，能夠抑制在Mg 合金板表面因洗淨液所產生之腐蝕。 藉由在除水製程後具有乾燥製程，即使在進行除水製 程後，洗淨液殘存於Mg合金板的表面，也能夠藉由乾燥製 程，防止洗淨液殘存於Mg合金板的表面。因此，能夠縮短 洗淨液與Mg合金板的表面接觸之時間。 當將在硏磨製程所加工的Mg合金板的表面作成越平滑 ，則當Mg合金板的表面產生污漬、著色等時，變得越顯眼 。因此，藉由除水、乾燥製程將Mg合金板表面的洗淨液充 分地除去，在對符合前述規定之表面粗糙度加工Mg合金板 的表面之情況，在排除伴隨Mg合金板表面的微小腐蝕之污 漬、著色等上特別有效果。 201143970 藉由在線內進行前述硏磨、洗淨、除水、乾燥的各製 程，如上述，能夠分別縮短在各製程間，液體附著於Mg合 金板的表面之時間。因此，在如前述規定，表面呈平滑之 情況，能夠製造出因腐蝕所引起之污漬、著色等不顯眼且 具優良之金屬質感的Mg合金板。 作爲本發明方法之一形態可舉出，在前述洗淨製程之 前，還具備將附著於前述Mg合金板之前述硏磨液除去的除 液製程》 若依據前述結構，藉由在洗淨製程之前，還具有用來 除去因進行硏磨而附著於Mg合金板之硏磨液的除液製程， 能夠在洗淨製程沖洗硏磨液之前，藉由除液製程除去硏磨 液。即，可更迅速地除去硏磨液，能夠進一步縮短Mg合金 板與硏磨液接觸之時間。 作爲本發明方法之一形態可舉出，前述硏磨製程之目 的係使表面粗糙度符合算術平均粗糙度RaS 0.6 μπι、最大 高度RmaxS ΙΟμπι、及十點平均高度Ι1ζ$6μιη中的至少其中 —者。 若依據前述結構，當將在硏磨製程所加工的Mg合金板 的表面作成越平滑，則當Mg合金板的表面產生污漬、著色 等時，變得越顯眼。因此，藉由除水、乾燥製程將Mg合金 板表面的洗淨液充分地除去，在對符合前述規定之表面粗 糙度加工Mg合金板的表面之情況，在排除伴隨Mg合金板 表面的微小腐蝕之污漬、著色等上特別有效果。 作爲本發明方法之一形態可舉出，前述乾燥製程係以 -8- 201143970 40°C以上的空氣噴吹來實施。 若依據前述結構，即使在例如洗淨液殘存於Mg合金板 的表面之情況，也能將洗淨液更迅速且容易乾燥，因此， 能夠抑制洗淨液殘存於Mg合金板表面。 作爲本發明方法之一形態可舉出，硏磨液及洗淨液中 的至少其中一方爲4(TC以上。 若依據前述結構，在之後的乾燥製程，能夠容易乾燥 前述液體，可抑制前述液體殘存於Mg合金板的表面。 作爲本發明方法之一形態可舉出，Mg合金板的搬送速 度爲5m/min以上》 若依據前述結構，藉由增快Mg合金板的搬送速度，能 夠縮短從前述液體附著於Mg合金板的表面到除去前述液體 爲止之時間，因此，能夠縮短Mg合金板的表面被硏磨液、 洗淨液等弄濕的時間。 作爲本發明方法之一形態可舉出，前述搬送速度爲 1 Om/min以上。 若依據前述結構，藉由增快Mg合金板的搬送速度，能 夠進一步縮短從前述液體附著於Mg合金板的表面到除去前 述液體爲止之時間，因此，能夠更縮短Mg合金板的表面被 硏磨液、洗淨液等弄濕的時間。 本發明的Mg合金板係爲藉由上述之Mg合金板的表面 加工方法所製造的Mg合金板。 若依據前述結構，Mg合金板，雖表面平滑，但，不會 有因腐蝕所引起之污漬、著色等顯眼的情況產生，具有優 -9 - 201143970 良之金屬質感。 作爲本發明Mg合金板的一形態可舉出，Mg合金板係 由含有鋁（以下、A1 )之Mg合金所構成。 若依據前述結構，藉由含有A1’可進一步提升Mg合金 板的耐腐蝕性，因此Mg合金表面變得更不易腐蝕，污漬、 著色等變得更不顯眼。 作爲本發明Mg合金板的一形態可舉出，Mg合金板係 由含有A1之Mg合金所構成，其組成爲含有8.3質量％以上 9.5質量％以下之A1。 若依據前述結構，藉由含有8.3質量％以上9.5質量％以 下之A1’可進一步提升Mg合金板的耐腐蝕性，因此，Mg 合金表面變得更不易腐蝕，污漬、著色等變得更不顯眼。 〔發明效果〕 本發明的Mg合金板的表面加工方法，在將Mg合金板 的表面濕式硏磨成平滑之情況，能夠使得在M g合金板的表 面，污漬、著色等不顯眼。 本發明的Mg合金板係藉由使用本發明的Mg合金板的 表面加工方法來製造，能夠作成爲污漬、著色等在Mg合金 板的表面不顯眼者。 【實施方式】 < <實施形態1> > 以下，說明關於本發明的實施形態。在此，說明對長 -10- 201143970 條狀的Mg合金板實施表面加工之Mg合金板的表面加工方 法的順序。此表面加工方法係如圖1所示，對自反復送出 滾子S反復送出之Mg合金板W，實施硏磨製程1、洗淨製程 2、除水製程3、及乾燥製程4後，以捲取滾子E捲取該Mg 合金板W，將該等製程在線內進行之方法。本發明的特徵 係在於縮短在前述製程所使用之液體與Mg合金板W接觸之 時間。以下、依序說明各製程，之後說明關於加工對象之 Mg合金板。 <表面加工方法〉 〔硏磨製程〕 自反復送出滾子S將Mg合金板W捲回並搬送，對該搬 送之Mg合金板W實施硏磨加工。此硏磨加工係在使用硏磨 液13的狀態下，藉由硏磨材將前述Mg合金板W的表面進行 硏磨。硏磨材係使用硏磨皮帶1A。硏磨皮帶1 A的砥粒的 粒度係可適宜選擇，使得Mg合金板W的表面粗糙度成爲期 望的粗糙度，但，理想爲#3 20以上，更理想爲#400，特別 理想爲#600以上。若可硏磨成後述的預定表面粗糙度，則 不限定硏磨材之形態。例如，除皮帶以外，亦可將刷或輪 等的砥石等，使用於硏磨材。 前述預定表面粗糙度係指符合算術平均粗糙度Ra S 1·2μιη、最大高度Rmax S 20μιη、及十點平均高度RZ$ 12μιη中的至少一者。更理想爲符合算術平均粗糙度Rag 〇.6 4111、最大高度1111^义$1(^111、及十點平均高度1^$6 0111 -11 - 201143970 中的至少其中一者。 在本例，分2段階實施硏磨加工。在該情況，例如， 以Mg合金板W的上游側的硏磨皮帶10爲#3 20 (#4 00)、下 游側的硏磨皮帶1 1爲#400 ( #600 )這樣之2段階的硏磨皮 帶1 A，係在該砥粒的粒度，將前述下游側作成爲較前述上 游側更細小爲佳。藉此，能夠將Mg合金板W的表面更均等 且平滑地予以硏磨。即使在將硏磨加工設置成3段階以上 之情況，亦與前述2段階時同樣地，設計成自上游側朝下 游側，砥粒的粒度變細小爲佳。 此硏磨加工係對Mg合金板W的表裏面實施。在此，設 置於表裏面之硏磨皮帶1 A係相互偏移位在Mg合金板W的長 方向。在隔著Mg合金W的表裏面而硏磨皮帶1A之相對向的 位置，設有基準滾子（未圖示）。藉由設置前述基準滾子 ，能夠容易將Mg合金板W的表裏面之硏磨量作成更均等。 以藉由前述偏移，使得Mg合金板W的裏面（垂直下方側） 先被硏磨的方式設置硏磨皮帶1 A爲佳。在先將前述裏面進 行硏磨加工之情況，硏磨液13之噴射也是前述裏面側先進 行，但，因該硏磨液13不會迂迴進入到Mg合金板W的表面 ，在前述表裏面上，變得容易控制與硏磨液13接觸之接觸 開始位置。又，硏磨皮帶1A亦可位於隔著Mg合金板W的表 裏面而相對向的位置。硏磨皮帶1 A之硏磨形式係朝與Mg 合金板W的搬送方向相同方向旋轉之順銑（down cut)爲 佳。藉此，能夠實施可獲得更平滑的Mg合金板之硏磨。但 ，在要求硏磨效率之情況，亦可進行硏磨皮帶1A朝與Mg -12- 201143970 合金板W的搬送方向相反方向旋轉之逆銑。特別是當考量 硏磨效率與硏磨面之平滑性兩立時，亦可將上游側的硏磨 皮帶1 〇作成爲逆銑，而將下游側的硏磨皮帶11作成爲順銑 當進行硏磨時，硏磨液13係自對硏磨皮帶10、11配置 於Mg合金板W的上游側、下游側雙方之噴霧噴嘴12噴射。 特別是如本例這種順銑之情況，在前述下游側，亦可設置 亦可不設置噴霧噴嘴1 2。即，亦可僅在上游側、下游側中 的其中一方具有噴霧噴嘴I2。特別是當考量對硏磨皮帶10 、1 1與Mg合金板W之間充分地供給硏磨液13時，若爲前述 逆銑則在下游側，若爲前述順銑則在上游側，配置噴霧噴 嘴12爲佳》藉此，能夠減低因硏磨造成Mg合金板W與硏磨 皮帶1A所產生之摩擦熱、及摩擦抵抗。又，前述逆銑之情 況，在上游側配置噴霧噴嘴12，前述順銑之情況，在下游 側配置噴霧噴嘴12時，硏磨液13排出硏磨粉，可容易抑制 硏磨粉堵塞於硏磨皮帶1A與Mg合金板W之間的情況產生。 硏磨液13，若爲Mg合金板W不易腐蝕者、能夠減低因 硏磨所產生之Mg合金板W與硏磨皮帶1A的摩擦熱及摩擦抵 抗者、或可排出硏磨粉而能抑制研磨粉堵塞於硏磨皮帶1A 與Mg合金板W之間的情況產生者，則未特別限制。藉由使 用硏磨液13，即使硏磨對象爲Mg合金這樣的活性物質，也 能防止硏磨粉產生粉塵爆炸。 〔洗淨製程〕 -13- 201143970 在洗淨製程2，藉由洗淨液21，沖洗附著於在實施了 前述硏磨加工後的Mg合金板W上之硏磨液13。在本例，洗 淨液21係使用水。洗淨液21，若爲可沖洗硏磨液13，且不 會與硏磨對象產生反應者，則未特別限制。 在洗淨製程2，噴出洗淨液21之洗淨噴嘴20係可配置 於隔著Mg合金板W的表裏面而相對向之位置。藉此’在 Mg合金板W的表裏面之液體的除去程度上幾乎不會產生差 異，能夠沖洗硏磨液13，能夠容許因硏磨皮帶1A的偏移所 產生之Mg合金板W的表裏面之與液體接觸的時間差。又， 亦可與硏磨皮帶1A同樣地，Mg合金板W的表裏面之洗淨噴 嘴20位於朝Mg合金板W的長方向偏移之位置。藉此，能夠 使得在表裏面上，與液體接觸之時間不會產生差。 〔除水製程〕 在除水製程3，除去附著於經過了洗淨製程2之Mg合金 板W上的洗淨液21。爲了除去洗淨液21，使用如海綿製的 除水滾子30這種可充分地除去洗淨液21者爲佳。另外，若 可均等地除去洗淨液2 1，亦可將橡膠製的除水刷、氈子、 利用壓縮空氣之空氣刀、或空氣簾等使用於除水製程3。 除水滾子30係具有與Mg合金板W的寬度相等以上的寬度爲 佳。藉此，在附著有洗淨液的Mg合金板W之寬度方向上不 會產生擦拭遺漏，可進行均等的擦拭。 除水滾子30係設置於隔著Mg合金板W的表裏面而相對 向之位置。藉此，在Mg合金板W的表裏面之液體的除去程 -14- 201143970 度上不會產生差異，可擦拭洗淨液21’因此’在表裏面中 ，與液體接觸之時間不易產生差。又’與硏磨皮帶1A同樣 地，在洗淨噴嘴20朝Mg合金板W的長方向偏移之情況， Mg合金板W的表裏面之除水滾子30也可同樣地配置成朝長 方向偏移。在該情況，也能夠使得在表裏面中，與液體接 觸之時間不易產生差。除水製程3亦可設置成3段階以上。 藉此，可更確實地除去洗淨液21。 〔乾燥製程〕 在乾燥製程4，因在除水製程3後，會有洗淨液21殘存 於Mg合金板W之可能性，因此，爲了不會殘存有洗淨液2 1 ，而將洗淨液21予以乾燥。作爲乾燥之手段，進行空氣噴 吹爲佳。特別是40°C以上的溫風爲更佳。 乾燥製程4也與除水製程3同樣地，能夠在隔著Mg合金 板W的表裏面而相對向之位置，設置用來噴出空氣41之送 風口 40。藉此，就算洗淨液21殘存於Mg合金板W的表面， 在Mg合金板W的表裏面，也能於相同位置予以乾燥，因此 ，在表裏面，於與液體接觸之時間上不會產生差。如上述 ，在除水滾子30朝Mg合金板W的長方向偏移之情況，Mg 合金板W的表裏面之送風.口 40亦可同樣地設置成朝長方向 偏移。在該情況也同樣地能夠在表裏面，於與液體接觸之 時間上不易產生差。 在本例，雖空氣噴吹僅設置1段階，但，若爲了可更 確實地除去洗淨液2 1，將乾燥製程4設置成2段階爲佳。在 -15- 201143970 該情況，在乾燥效率的觀點上，將上游側、下游側的至少 其中一方的乾燥製程作成爲40t以上的溫風爲佳。例如， 將上游側的空氣之溫度作成爲40°C以上，而將下游側的空 氣之溫度作成爲較上游側的溫度低，則既可藉由2段階之 空氣來提高乾燥的確實性，又，比起將兩段階之空氣作成 爲40°C以上之情況，能夠減少在乾燥製程4之消耗能量。 (其他） 前述各製程係在線內進行。此時，Mg合金板W的搬送 速度係較快爲佳。該速度爲5m/min以上，特別是10m/min 以上爲更佳。 <被加工材> 實施前述表面加工方法之Mg合金板W係爲對由鑄造所 獲得的材料實施輥軋者爲佳。其他，亦可將對鑄造材、輥 軋材實施整平加工者作爲被加工材。這些被加工材，亦可 在進行輥軋前實施溶體化處理。 〔形狀〕 在本例，使用捲繞成線圈狀之長條帶狀Mg合金板W， 但，對加工對象未特別限定，例如，亦可爲短條帶狀板。 例如，若要作成線圈狀，則以連續鑄造來成形，而要作成 短條帶狀板，則以壓鑄等來成形爲佳。又，亦可長條帶狀 板裁斷成所需尺寸來製作短條帶狀板。 -16- 201143970 〔組成〕 作爲Mg合金板W，可舉出對Mg添加各種元素者。添 加元素可舉出例如，Al、Zn、Mn、Si、Cu、Ag、Y、Zr等 之元素群中的至少一種元素。亦可含有自前述元素群所選 擇之複數種元素。具體而言，若爲ASTM規格之AZ系，則 可利用如AZ31、AZ61、AZ91等’若爲AM系，則可利用如 AM60等，另外，亦可利用AS系' ZK系等的Mg合金。特別 是在耐腐蝕性、強度高的觀點上，含有 8.3質量％〜9.5質 量％之A1的AZ91爲佳。 <作用效果> 若依據上述實施形態1之Mg合金板的表面加工方法， 在將Mg合金板的表面進行濕式硏磨成平滑之情況，藉由除 水及乾燥製程，使得在Mg合金板的表面不易產生因腐蝕所 引起之污漬、著色等。因此，容易獲得金屬質感高的Mg合 金板。 < <實施形態2 > > 依據圖2說明關於，與實施形態1不同之實施形態。在 本例，與實施形態1同樣地，對自反復送出滾子S反復送出 之Mg合金板W實施硏磨製程1、洗淨製程2、除水製程3、 及乾燥製程4，然後，以捲取滾子E捲繞Mg合金板W，將這 些所有的製程在線內進行。但，在硏磨製程1與洗淨製程2 -17- 201143970 之間，尙具有用來除去硏磨液之除液製程5。本例之表面 加工方法，其基本結構與實施形態1相同，因此，以下， 僅針對與實施形態1不同點進行說明。圖2中，與圖1相同 之符號係顯示相同物。 〔除液製程〕 在此，在硏磨製程1與洗淨製程2之間，具有用來除去 硏磨液13之除液製程5。在藉由洗淨液21沖洗硏磨液13之 間，藉由例如，由與在除水製程3所使用的除水滾子3 0相 同之海綿所構成的除液滾子5 0來除去硏磨液13，能夠極力 地縮短Mg合金板W的表面與硏磨液13接觸之時間。因此， 可進一步抑制Mg合金板W的腐蝕。另外，若能均等地除去 硏磨液13，則亦可將橡膠製的除液刷、氈子、利用壓縮空 氣之空氣刀、或空氣簾等使用於除液製程5。除液滾子50 也具有與Mg合金板W相同或相同以上的寬度爲佳。在如本 例這種將硏磨加工分成2段階來實施之情況，各段階間， 即在硏磨皮帶10與硏磨皮帶11之間亦設置前述除液滾子50 時，則能夠更進一步縮短硏磨液13接觸於Mg合金板W之時 間，因此極爲理想。 <作用效果> 若依據上述實施形態2之Mg合金板的表面加工方法， 在將Mg合金板的表面進行濕式硏磨成平滑之情況’藉由除 液、除水及乾燥製程，使得在Mg合金板的表面不易產生因 -18 - 201143970 腐鈾所引起之污漬、著色等》因此，容易獲得金屬質感更 高的Mg合金板。 <實驗例> 作爲實驗例，準備將Mg合金板W捲繞成線圈狀者，再 將該Mg合金板W以圖1、2所示的表面加工方法之順序，並 以硏磨皮帶之砥粒作成各種粒度來實施表面加工。在該表 面加工後，測定Mg合金板W的表面粗糙度。又，目視該 Mg合金板W的表面，比較污漬、著色等之程度。 作爲加工對象，Mg合金板W係使用將具有含Mg-9.0質 量％人1-1.0質量％Zn之相當於AZ91的組成，由雙滾子連續 鑄造所製造之Mg合金板捲繞成線圈狀者。對該Mg合金線 圈，以底下所示的表面加工條件實施表面加工。又，將硏 磨皮帶之胝粒的粒度進行各種變更，製作試料1〜15。但 ，試料1〜5係以圖1所示的順序，試料6〜1 〇係以圖2所示 的順序’試料1 1〜1 5係以不含圖1之除水製程以外的順序 分別實施者。 〔表面加工條件〕 硏磨方法：濕式皮帶硏磨 砥粒的最終號：試料No.l、6、1 1-#320 試料 Νο·2、7、1 2-#400 試料 Νο.3、8、1 3-#600 試料 Νο.4、9、14-#180 -19- 201143970 試料 Νο·5、1 Ο、1 5-#240 Mg合金板的搬送速度：5m/min 硏磨皮帶的周速：1200m/min 硏磨液的溫度：40°C 洗淨液的溫度：40°C 乾燥製程：4〇°C之空氣噴吹 然後，測定試料1〜15之表面粗糙度，並觀察該表® 。其結果顯示於表1。此表中的以下標記係指下述意思° 表面狀態：未見污漬、著色等者以〇表示，污漬、著 色等不顯眼者以△表示，可看到污漬或著色者以X表示。 20- 201143970 〔表1〕 試料No. 表面加工製程 抵粒最終號 算術平均 粗糙度Ra 最大局度 Rmax 十點平均高 度Rz 表面狀態 試料1 圖1 #320 1.2μιη 20μπι 12μηι 〇 試料2 圖1 #400 Ο.όμιη ΙΟμιη 6μιη 〇 試料3 圖1 #600 0.3μιη 5μπι 3μιη 〇 試料4 圖1 #180 1.8μπχ 30μηι 18μιη 〇 試料5 圖1 #240 1.4μπι 22μιη 14μιη 〇 試料6 圖2 #320 1.2μχη 20μιη 12μιη 〇 試料7 圖2 #400 Ο.όμηι ΙΟμιη 6μιη 〇 試料8 圖2 #600 0.3μιη 5μπι 3μιη 〇 試料9 圖2 #180 1.8μιη 30μηι 18μιη 〇 試料10 圖2 #240 1.4μπι 22μπι 14μιη 〇 試料11 圖1憮吸水製程) #320 1.2μηα 20μηι 12μιη X 試料12 圖1憮吸水製程) #400 Ο.όμιη ΙΟμιη 6μπ\ X 試料13 圖1憮吸水製程) #600 0.3μιη 5μιη 3μηι X 試料14 圖1憮吸水製程) #180 1.8μτη 30μιη 18μιη Δ 試料15 圖1憮吸水製程) #240 1.4μπι 22μπι 14μιη Δ <結果〉 在表面加工後，在試料No.1〜10之該表面未見污漬、 著色等。又，關於試料No. 1 1〜1 3，確認到污漬、著色等 。這是由於在表面加工，無法均等且迅速地除去附著於Mg 合金板之液體，該液體所接觸之部分的腐蝕行進之故，因 ，表面呈平滑，故著色等極爲顯眼。又，當測定各試料的 表面粗糙度時，算術平均粗糙度Ra S 1.2μιη、最大高度 Rmax $ 2 0μιη、十點平均高度Rz S 1 2μιη之表面粗糙度小， 平滑的試料No.l〜3、6〜8之表面沒有污漬、著色等產生 ，獲得優良金屬質感之Mg合金板。在此，將相同表面粗糙 -21 - 201143970 度彼此的試料No.l與6、2與7、3與8分別進行比較時得知 ’實施有圖2之表面加工方法的試料No.6〜8比較未見污漬 、著色等。又，關於試料No.4、5、9、10，雖未見污漬、 著色等’但，由於表面粗糙度粗，故獲得金屬質感較差之 Mg合金板。又，在超過前述表面粗糙度範圍之試料N〇 14 、15’雖有產生污漬、著色等，但該污漬、著色等不顯眼 ，不過獲得金屬質感差之Mg合金板。 以上所述得知，在硏磨製程後，若未除去附著於Mg合 金板的表面之液體，污漬、著色等變得顯眼，若實施本發 明的表面加工方法，能夠不易產生該污漬、著色等。特別 是在前述範圍的表面粗糙度非常小之情況，當實施本發明 的表面加工時，則可獲得不會產生污漬、著色等且具優良 金屬質感之Mg合金板。這是由於在實施形態1、2之本發明 的表面加工方法，當進行加工時能夠迅速地除去與Mg合金 板的表面接觸之液體，因此，能夠縮短Mg合金板與液體接 觸之時間，能夠抑制Mg合金板與液體之腐蝕之故。 再者，上述實施形態，在不超出本發明的技術思想範 圍下，能夠適宜變更，不限於上述結構。 〔產業上的利用可能性〕 本發明的Mg合金板的表面加工方法可利用於當欲將 Mg合金板的表面進行濕式硏磨成平滑的情況。 【圖式簡單說明】 -22- 201143970 圖1係用來說明實施形態1之表面加工方法的示意圖。 圖2係用來說明實施形態2之表面加工方法的示意圖。 [主要元件符號說明】 S:反復送出滾子 W : Mg合金板 1 :硏磨製程 1A、10、11:硏磨皮帶 12 :噴霧噴嘴 1 3 :硏磨液 2 :洗淨製程 2〇 :洗淨噴嘴 21 :洗淨液 3 :除水製程 3 〇 :除水滾子 4:乾燥製程 4 〇 :送風口 41 :空氣 5:除液製程 50 :除液滾子 E :捲取滾子 -23-[Technical Field] The present invention relates to a surface processing method of a magnesium alloy sheet, and a magnesium alloy sheet produced by the surface processing method. In particular, in the case where the surface of the magnesium alloy sheet is smoothed, an inconspicuous surface processing method such as staining or coloring on the surface of the magnesium alloy sheet, and a magnesium alloy sheet produced by the surface processing are used. [Prior Art] In recent years, magnesium (hereinafter referred to as Mg) alloy sheets have been gradually used in housings such as mobile phones and notebook computers. For example, in the post-process, it is described that the Mg alloy sheet can be subjected to fine uneven processing uniformly, and the rolled material of the Mg alloy can be subjected to honing processing as a preliminary processing. As a representative example of this honing process, a wet belt type honing is mentioned. [Problem to be Solved by the Invention] In recent years, a Mg alloy plate having a higher metallic texture has been required. In response to such a demand, the conditions of the aforementioned honing processing were tested. As a result, when the surface of the Mg alloy sheet is wet-honed to a smoother condition, there is a case where the surface of the Mg alloy sheet is stained or colored, and the presence of such stains, coloring, etc. may become a Mg alloy. The reason for the improvement of the metal texture of the board. -5- 201143970 The present invention has been developed in view of the foregoing, and an object of the invention is to provide a method of wet-grinding the surface of a Mg alloy sheet to smooth the surface of the alloy sheet. A surface processing method for conspicuous Mg alloy sheets. Another object of the present invention is to provide a Mg alloy sheet produced by the above surface processing method of the present invention. [Means for Solving the Problem] The present inventors carefully examined the causes of stains, coloring, and the like which are generated on the surface of the Mg alloy sheet. As a result, the following findings were obtained. (1) If the surface of the Mg alloy sheet is wet-honed, the surface of the Mg alloy sheet is cut to produce a new surface which is exposed to the honing liquid and the cleaning liquid to cause corrosion, which may become stains, One reason for coloring, etc. (2) If the surface of the Mg alloy sheet is thick, it is less conspicuous, but the smoother the same surface is, the more conspicuous it is. (3) Even the honing liquid, the cleaning liquid, etc. The contact time with the new surface is extremely short, and the aforementioned corrosion also travels. The present invention has been developed in accordance with the foregoing findings, which achieves the aforementioned object by reducing the contact time of the Mg alloy sheet with the liquid used in the wet honing process. The surface processing method of the Mg alloy sheet of the present invention has: a honing process: a washing process; a water removing process; and a drying process. In the honing process, the surface of the transferred Mg alloy sheet is honed by the honing material while the honing liquid is used in -6-201143970. In the washing process, after the honing process, the honing liquid attached to the Mg alloy plate is washed with a washing liquid. After the dewatering process, the cleaning process attached to the Mg alloy plate is removed after the cleaning process. In the drying process, the washing liquid remaining on the surface of the Mg alloy sheet which cannot be completely removed by the water removing process is dried. And in the honing process, the purpose is to make the surface roughness of the Mg alloy sheet conform to at least one of arithmetic mean roughness RaS 1.2 μπι, maximum height RmaxS20pm, and ten-point average height Rz$12pm. Further, each of the processes of honing, washing, water removal, and drying is carried out in-line. According to the above configuration, the cleaning liquid used in the cleaning process can be removed by having a water removal process after the cleaning process. . Therefore, since the time during which the cleaning liquid adheres to the surface of the Mg alloy sheet becomes short, corrosion due to the cleaning liquid on the surface of the Mg alloy sheet can be suppressed. By having a drying process after the water removal process, even if the cleaning liquid remains on the surface of the Mg alloy plate after the water removal process, the cleaning process can prevent the cleaning liquid from remaining on the surface of the Mg alloy plate. Therefore, the time during which the cleaning liquid comes into contact with the surface of the Mg alloy plate can be shortened. When the surface of the Mg alloy sheet processed in the honing process is made smoother, when the surface of the Mg alloy sheet is stained, colored, or the like, it becomes more conspicuous. Therefore, the cleaning liquid on the surface of the Mg alloy sheet is sufficiently removed by the water removal and drying processes, and the surface of the Mg alloy sheet is processed to meet the aforementioned surface roughness, and the micro-corrosion accompanying the surface of the Mg alloy sheet is excluded. It is particularly effective in stains, coloring, and the like. 201143970 By performing the above-described processes of honing, washing, water removal, and drying in the line, as described above, the time during which the liquid adheres to the surface of the Mg alloy plate can be shortened in each process. Therefore, in the case where the surface is smooth as described above, it is possible to produce a Mg alloy sheet which is inconspicuous and has an excellent metallic texture such as stains and coloring due to corrosion. In one embodiment of the method of the present invention, before the cleaning process, a liquid removal process for removing the honing liquid adhered to the Mg alloy plate is provided. According to the above configuration, before the cleaning process Further, there is a liquid removal process for removing the honing liquid attached to the Mg alloy plate by honing, and the honing liquid can be removed by the liquid removal process before the rinsing liquid is washed by the cleaning process. That is, the honing liquid can be removed more quickly, and the time during which the Mg alloy plate is in contact with the honing liquid can be further shortened. In one embodiment of the method of the present invention, the honing process is performed such that the surface roughness conforms to at least one of arithmetic mean roughness RaS 0.6 μπι, maximum height RmaxS ΙΟμπι, and ten-point average height Ι1ζ$6μιη. . According to the above configuration, when the surface of the Mg alloy sheet processed in the honing process is made smoother, the surface of the Mg alloy sheet becomes more conspicuous when stains, coloring, and the like are formed. Therefore, the cleaning liquid on the surface of the Mg alloy sheet is sufficiently removed by the water removal and drying processes, and the surface of the Mg alloy sheet is processed to meet the aforementioned surface roughness, and the micro-corrosion accompanying the surface of the Mg alloy sheet is excluded. It is particularly effective in stains, coloring, and the like. In one embodiment of the method of the present invention, the drying process is carried out by air blowing at -8 to 201143970 40 ° C or higher. According to the above configuration, even when the cleaning liquid remains on the surface of the Mg alloy sheet, the cleaning liquid can be more quickly and easily dried. Therefore, it is possible to prevent the cleaning liquid from remaining on the surface of the Mg alloy sheet. In one embodiment of the method of the present invention, at least one of the honing liquid and the cleaning liquid is 4 (TC or more. According to the above configuration, the liquid can be easily dried in a subsequent drying process, and the liquid can be suppressed. In the form of one of the methods of the present invention, the conveying speed of the Mg alloy sheet is 5 m/min or more. According to the above configuration, the conveying speed of the Mg alloy sheet can be shortened. Since the liquid adheres to the surface of the Mg alloy sheet to the time of removing the liquid, the surface of the Mg alloy sheet can be shortened by the honing liquid, the cleaning liquid, etc., which is one of the methods of the present invention. The transport speed is 1 Om/min or more. According to the above configuration, by increasing the transport speed of the Mg alloy sheet, the time from the adhesion of the liquid to the surface of the Mg alloy sheet to the removal of the liquid can be further shortened. It is possible to shorten the time when the surface of the Mg alloy sheet is wetted by the honing liquid, the cleaning liquid, etc. The Mg alloy sheet of the present invention is the surface of the Mg alloy sheet described above. According to the above structure, the Mg alloy plate has a smooth surface, but does not cause conspicuous conditions such as stains and coloring due to corrosion, and has a good metal texture of excellent -9 - 201143970 As an aspect of the Mg alloy sheet of the present invention, the Mg alloy sheet is composed of a Mg alloy containing aluminum (hereinafter, A1). According to the above configuration, the resistance of the Mg alloy sheet can be further improved by containing A1'. Corrosion, the surface of the Mg alloy becomes less corrosive, and stains, coloring, and the like become less conspicuous. As an aspect of the Mg alloy sheet of the present invention, the Mg alloy sheet is composed of a Mg alloy containing A1, and The composition contains 8.3% by mass or more and 9.5% by mass or less of A1. According to the above configuration, the corrosion resistance of the Mg alloy sheet can be further improved by containing 8.3 mass% or more and 9.5% by mass or less of A1', and therefore, the surface of the Mg alloy is changed. [Effect of the invention] The surface processing method of the Mg alloy sheet of the present invention is performed by wet honing the surface of the Mg alloy sheet into In the case of slipping, the surface of the Mg alloy sheet, stains, coloring, and the like can be made inconspicuous. The Mg alloy sheet of the present invention is produced by the surface processing method using the Mg alloy sheet of the present invention, and can be used as stains and stains. [Embodiment] <Embodiment 1> > Hereinafter, embodiments of the present invention will be described. Here, a description will be given of a Mg alloy having a length of -10 201143970. The order of the surface processing method of the surface-processed Mg alloy sheet is performed. The surface processing method is as shown in Fig. 1, and the honing process and the cleaning process are performed on the Mg alloy sheet W which is repeatedly fed out from the repeatedly fed roller S. 2. After the water removal process 3 and the drying process 4, the Mg alloy plate W is taken up by the take-up roller E, and the processes are carried out in-line. The present invention is characterized by shortening the time during which the liquid used in the aforementioned process is in contact with the Mg alloy sheet W. Hereinafter, each process will be described in order, and then the Mg alloy sheet to be processed will be described. <Surface processing method> [honing process] The Mg alloy sheet W is wound up and transported by repeatedly feeding the roller S, and the conveyed Mg alloy sheet W is subjected to honing processing. In the honing processing, the surface of the Mg alloy sheet W is honed by a honing material in a state where the honing liquid 13 is used. The honing material is honing the belt 1A. The particle size of the cerium of the honing belt 1 A can be appropriately selected so that the surface roughness of the Mg alloy sheet W becomes a desired roughness, but it is preferably #3 20 or more, more preferably #400, and particularly preferably #600. the above. The shape of the honing material is not limited if it can be honed to a predetermined surface roughness to be described later. For example, in addition to the belt, a vermiculite such as a brush or a wheel may be used for the honing material. The predetermined surface roughness refers to at least one of the arithmetic mean roughness Ra S 1·2 μηη, the maximum height Rmax S 20 μιη, and the ten-point average height RZ$12 μιη. More preferably, it is at least one of arithmetic mean roughness Rag 〇.6 4111, maximum height 1111^=$1 (^111, and ten-point average height 1^$6 0111 -11 - 201143970. In this example, minute 2 In this case, for example, the honing belt 10 on the upstream side of the Mg alloy sheet W is #3 20 (#4 00), and the honing belt 1 1 on the downstream side is #400 (#600). The honing belt 1 A of the two-stage step is preferably such that the downstream side is made finer than the upstream side in the particle size of the granules, whereby the surface of the Mg alloy sheet W can be more evenly and smoothly In the case where the honing processing is set to the third step or more, it is preferable to design the granules to be smaller from the upstream side to the downstream side in the same manner as in the second step. The inner surface of the Mg alloy sheet W is applied. Here, the honing belts 1 A provided in the front surface are offset from each other in the longitudinal direction of the Mg alloy sheet W. The belt is honed in the surface of the Mg alloy W. A reference roller (not shown) is provided at a position facing 1A. By providing the aforementioned reference roller, It is easy to make the amount of honing in the surface of the Mg alloy sheet W more uniform. It is preferable to set the honing belt 1 A by honing the inside (lower vertical side) of the Mg alloy sheet W by the aforementioned offset. In the case where the above-mentioned inside is honed, the injection of the honing liquid 13 is also performed on the inner side first, but since the honing liquid 13 does not wander back into the surface of the Mg alloy sheet W, in the above table In this case, it is easy to control the contact start position in contact with the honing liquid 13. Further, the honing belt 1A may be located at a position opposed to the inside of the front surface of the Mg alloy sheet W. The honing pattern of the honing belt 1 A It is preferable to perform a down cut which is rotated in the same direction as the transport direction of the Mg alloy sheet W. Thereby, it is possible to perform honing which can obtain a smoother Mg alloy sheet. However, in the case where honing efficiency is required, It is also possible to perform up-cutting of the honing belt 1A in the opposite direction to the conveying direction of the Mg -12- 201143970 alloy sheet W. Especially when considering the honing efficiency and the smoothness of the honing surface, the upstream side can also be used. Honing belt 1 is made up-cut and will be down When the honing belt 11 on the side is honed and honed, the honing fluid 13 is sprayed from the spray nozzles 12 disposed on both the upstream side and the downstream side of the honing belts 10 and 11 on the Mg alloy sheet W. In the case of the down-milling in this example, the spray nozzle 12 may or may not be provided on the downstream side. That is, the spray nozzle I2 may be provided only on one of the upstream side and the downstream side. When the honing fluid 13 is sufficiently supplied between the honing belts 10 and 1 and the Mg alloy sheet W, it is preferable to arrange the spray nozzle 12 on the upstream side in the case of the above-mentioned down milling if the boring is performed on the downstream side. According to this, it is possible to reduce the frictional heat and frictional resistance generated by the honing of the Mg alloy sheet W and the honing belt 1A. Further, in the case of the reverse milling, the spray nozzle 12 is disposed on the upstream side, and when the spray nozzle 12 is disposed on the downstream side in the case of the down milling, the honing liquid 13 discharges the honing powder, and the honing powder clogging can be easily suppressed. A situation occurs between the belt 1A and the Mg alloy sheet W. When the honing liquid 13 is not corroded by the Mg alloy sheet W, the friction heat and friction resistance of the Mg alloy sheet W and the honing belt 1A due to honing can be reduced, or the honing powder can be discharged to suppress the grinding. The case where the powder is clogged between the honing belt 1A and the Mg alloy sheet W is not particularly limited. By using the honing liquid 13, even if the honing object is an active material such as a Mg alloy, it is possible to prevent the honing powder from generating a dust explosion. [Washing Process] -13- 201143970 In the cleaning process 2, the cleaning liquid 21 is used to rinse the honing liquid 13 adhering to the Mg alloy sheet W subjected to the honing process. In this example, the cleaning solution 21 uses water. The cleaning liquid 21 is not particularly limited as long as it is a washable honing liquid 13 and does not react with the honing object. In the cleaning process 2, the cleaning nozzles 20 for ejecting the cleaning liquid 21 can be disposed at positions facing each other across the front surface of the Mg alloy sheet W. Therefore, the degree of removal of the liquid in the surface of the Mg alloy sheet W is hardly changed, and the honing liquid 13 can be washed, and the inside of the Mg alloy sheet W which is caused by the offset of the honing belt 1A can be accommodated. The time difference between contact with the liquid. Further, similarly to the honing belt 1A, the cleaning nozzle 20 on the front surface of the Mg alloy sheet W is located at a position shifted toward the longitudinal direction of the Mg alloy sheet W. Thereby, it is possible to make a difference in the time of contact with the liquid on the inside of the watch. [Water Removal Process] In the water removal process 3, the cleaning liquid 21 adhering to the Mg alloy sheet W subjected to the cleaning process 2 is removed. In order to remove the cleaning liquid 21, it is preferable to use a water-removing roller 30 such as a sponge to sufficiently remove the cleaning liquid 21. Further, if the cleaning liquid 2 1 can be uniformly removed, a water removing brush, a felt, an air knife using compressed air, or an air curtain can be used for the water removing process 3. The water removing roller 30 has a width equal to or greater than the width of the Mg alloy sheet W. Thereby, no wiping omission occurs in the width direction of the Mg alloy sheet W to which the cleaning liquid adheres, and uniform wiping can be performed. The water removing roller 30 is disposed at a position opposed to the inside of the surface of the Mg alloy sheet W. Thereby, there is no difference in the degree of removal of the liquid in the surface of the Mg alloy sheet W -14-201143970, and the cleaning liquid 21' can be wiped off. Therefore, in the inside of the watch, the time of contact with the liquid is less likely to be inferior. In the same manner as the honing belt 1A, when the cleaning nozzle 20 is displaced in the longitudinal direction of the Mg alloy sheet W, the water-removing roller 30 in the front surface of the Mg alloy sheet W can be similarly arranged in the longitudinal direction. Offset. In this case as well, it is possible to make it difficult to cause a difference in the time of contact with the liquid in the inside of the watch. The water removal process 3 can also be set to be more than 3 steps. Thereby, the cleaning liquid 21 can be removed more reliably. [Drying Process] In the drying process 4, since the cleaning liquid 21 remains in the Mg alloy sheet W after the water removing process 3, the cleaning liquid 2 1 will be washed away. The liquid 21 is dried. As a means of drying, air blowing is preferred. In particular, warm air of 40 ° C or higher is more preferable. Similarly to the water removal process 3, the drying process 4 can be provided with a blow port 40 for ejecting the air 41 at a position facing the inside of the front surface of the Mg alloy plate W. Thereby, even if the cleaning liquid 21 remains on the surface of the Mg alloy sheet W, it can be dried at the same position in the front surface of the Mg alloy sheet W, and therefore, the inside of the watch does not occur at the time of contact with the liquid. difference. As described above, when the water removing roller 30 is displaced in the longitudinal direction of the Mg alloy sheet W, the air supply port 40 in the front surface of the Mg alloy sheet W can be similarly disposed to be displaced in the longitudinal direction. Also in this case, in the table, it is possible to make a difference in the time of contact with the liquid. In this example, although the air blowing is only provided in one step, it is preferable to set the drying process 4 to the second step in order to more reliably remove the cleaning liquid 2 1. In the case of -15-201143970, it is preferable to make the drying process of at least one of the upstream side and the downstream side into a warm air of 40 t or more from the viewpoint of drying efficiency. For example, when the temperature of the air on the upstream side is 40° C. or higher and the temperature of the air on the downstream side is lower than the temperature on the upstream side, the accuracy of the drying can be improved by the air of the second stage. The energy consumption in the drying process 4 can be reduced as compared with the case where the air of two stages is made 40 ° C or higher. (Others) Each of the above processes is performed in-line. At this time, the transport speed of the Mg alloy sheet W is preferably faster. The speed is 5 m/min or more, and particularly preferably 10 m/min or more. <Materials to be processed> The Mg alloy sheet W on which the surface processing method is applied is preferably a roll for rolling a material obtained by casting. Others may be used as a material to be processed for the flattening of the cast material or the rolled material. These processed materials may be subjected to a solution treatment before rolling. [Shape] In this example, a long strip-shaped Mg alloy sheet W wound in a coil shape is used. However, the object to be processed is not particularly limited, and for example, a short strip-shaped sheet may be used. For example, if it is to be formed into a coil shape, it is formed by continuous casting, and if it is to be formed into a short strip-shaped plate, it is preferably formed by die casting or the like. Alternatively, the strip can be cut to a desired size to form a short strip. -16- 201143970 [Composition] As the Mg alloy sheet W, those in which various elements are added to Mg can be mentioned. The additive element may, for example, be at least one element selected from the group consisting of Al, Zn, Mn, Si, Cu, Ag, Y, Zr and the like. It may also contain a plurality of elements selected from the aforementioned group of elements. Specifically, in the case of the AZ system of the ASTM standard, for example, AZ31, AZ61, AZ91, etc. can be used. For the AM system, for example, AM60 or the like can be used, and a Mg alloy such as AS-based ZK can be used. In particular, AZ91 containing A1 of 8.3 mass% to 9.5 mass% is preferable from the viewpoint of corrosion resistance and high strength. <Operational Effect> According to the surface processing method of the Mg alloy sheet according to the first embodiment, when the surface of the Mg alloy sheet is wet-honed to be smooth, the water removal and drying processes are performed in the Mg alloy. The surface of the board is less likely to cause stains, coloring, and the like due to corrosion. Therefore, it is easy to obtain a Mg alloy plate having a high metallic texture. <<Embodiment2>> An embodiment different from the first embodiment will be described with reference to Fig. 2 . In this example, in the same manner as in the first embodiment, the Mg alloy sheet W repeatedly fed from the repeatedly fed roller S is subjected to a honing process 1, a cleaning process 2, a water removing process 3, and a drying process 4, and then, in a roll. Roller E is wound around the Mg alloy sheet W, and all of these processes are carried out in-line. However, between the honing process 1 and the cleaning process 2 -17- 201143970, the mash has a liquid removal process 5 for removing the honing liquid. The surface processing method of this example has the same basic configuration as that of the first embodiment. Therefore, only differences from the first embodiment will be described below. In Fig. 2, the same reference numerals as in Fig. 1 show the same. [Liquid removal process] Here, between the honing process 1 and the cleaning process 2, there is a liquid removal process 5 for removing the honing liquid 13. Between the honing liquid 13 and the honing liquid 13 by the cleaning liquid 21, for example, the liquid removing roller 50 composed of a sponge similar to the water removing roller 30 used in the water removing process 3 is used to remove the mash. The grinding liquid 13 can shorten the time during which the surface of the Mg alloy sheet W is in contact with the honing liquid 13 as much as possible. Therefore, the corrosion of the Mg alloy sheet W can be further suppressed. Further, if the honing liquid 13 can be uniformly removed, a rubber-made liquid removing brush, a felt, an air knife using compressed air, or an air curtain can be used for the liquid removing process 5. The liquid removing roller 50 also preferably has the same width or more than the Mg alloy sheet W. In the case where the honing process is divided into two stages as in the present example, the step of the liquid removal roller 50 is also provided between the honing belt 10 and the honing belt 11 in each step, thereby being further shortened. The time during which the honing fluid 13 is in contact with the Mg alloy sheet W is extremely desirable. <Operation and Effect> According to the surface processing method of the Mg alloy sheet according to the second embodiment, the surface of the Mg alloy sheet is wet-honed to be smoothed by the liquid removal, water removal, and drying processes. On the surface of the Mg alloy sheet, stains, coloring, etc. caused by uranium -18 - 201143970 are less likely to occur. Therefore, it is easy to obtain a Mg alloy sheet having a higher metal texture. <Experimental Example> As an experimental example, it is prepared to wind the Mg alloy sheet W into a coil shape, and the Mg alloy sheet W is in the order of the surface processing method shown in Figs. 1 and 2, and the honing belt is used. The granules are formed into various particle sizes to perform surface processing. After the surface was processed, the surface roughness of the Mg alloy sheet W was measured. Further, the surface of the Mg alloy sheet W was visually observed to compare the degree of staining, coloring, and the like. As the object to be processed, the Mg alloy sheet W is formed by winding a Mg alloy sheet produced by continuous casting of double rolls with a composition equivalent to AZ91 containing Mg-9.0% by mass of human 1-1.0% by mass of Zn. . The surface of the Mg alloy coil was subjected to surface processing under the surface processing conditions shown below. Further, the particle size of the granules of the honing belt was variously changed to prepare samples 1 to 15. However, the samples 1 to 5 are in the order shown in Fig. 1, and the samples 6 to 1 are in the order shown in Fig. 2, and the samples 1 1 to 1 are respectively executed in the order other than the water removal process of Fig. 1 . By. [Surface processing conditions] Honing method: Final number of wet belt honing granules: sample No.1, 6, 1 1-#320 Sample Νο·2, 7, 1 2-#400 Sample Νο.3, 8 , 1 3-#600 Sample Νο.4,9,14-#180 -19- 201143970 Sample Νο·5,1 Ο,1 5-#240 Transfer rate of Mg alloy plate: 5m/min Peripheral speed of honing belt :1200m/min Temperature of honing liquid: 40°C Temperature of washing liquid: 40°C Drying process: Air blowing at 4〇°C Then, measure the surface roughness of samples 1 to 15 and observe the table® . The results are shown in Table 1. The following marks in this table refer to the following meanings. Surface state: no stains, coloring, etc. are indicated by ,, stains, colors, etc. are not conspicuous, indicated by △, and stains or shaders are indicated by X. 20- 201143970 [Table 1] Sample No. Surface processing process granules final number arithmetic mean roughness Ra maximum degree Rmax ten point average height Rz surface state sample 1 Fig. 1 #320 1.2μιη 20μπι 12μηι 〇 sample 2 Fig. 1 #400 Ο.όμιη ΙΟμιη 6μιη 〇Sample 3 Figure 1 #600 0.3μιη 5μπι 3μιη 〇Sample 4 Figure 1 #180 1.8μπχ 30μηι 18μιη 〇Sample 5 Figure 1 #240 1.4μπι 22μιη 14μιη 〇Sample 6 Figure 2 #320 1.2μχη 20μιη 12μιη 〇 Sample 7 Figure 2 #400 Ο.όμηι ΙΟμιη 6μιη 〇Sample 8 Figure 2 #600 0.3μιη 5μπι 3μιη 〇Sample 9 Figure 2 #180 1.8μιη 30μηι 18μιη 〇Sample 10 Figure 2 #240 1.4μπι 22μπι 14μιη 〇 Sample 11 Figure 1怃Water absorption process) #320 1.2μηα 20μηι 12μιη X Sample 12 Figure 1 怃Water absorption process) #400 Ο.όμιη ΙΟμιη 6μπ\ X Sample 13 Figure 1 怃Water absorption process) #600 0.3μιη 5μιη 3μηι X Sample 14 Figure 1 怃Water absorption process) #180 1.8μτη 30μιη 18μιη Δ Sample 15 Figure 1 怃Water absorption process) #240 1.4μπι 22μπι 14μιη Δ < Fruit> After surface processing, no stains, coloring, or the like were observed on the surface of samples No. 1 to 10. Further, regarding the sample No. 1 1 to 1 3, stains, coloring, and the like were confirmed. This is because the surface is processed, and the liquid adhering to the Mg alloy plate cannot be removed uniformly and rapidly, and the corrosion of the portion in contact with the liquid proceeds because the surface is smooth, so that coloring and the like are conspicuous. Further, when the surface roughness of each sample was measured, the arithmetic mean roughness Ra S 1.2 μm, the maximum height Rmax $ 2 0 μιη, and the ten-point average height Rz S 1 2 μηη had a small surface roughness, and the smooth samples No. 1 to 3 The surface of 6 to 8 is free from stains, coloring, etc., and a Mg alloy plate having an excellent metallic texture is obtained. Here, when the samples No. 1 and 6, 2, and 7, 3, and 8 having the same surface roughness of 21 - 201143970 degrees were compared, respectively, it was found that the sample No. 6 to 8 having the surface processing method of Fig. 2 was carried out. No stains, coloring, etc. were observed. Further, in the samples Nos. 4, 5, 9, and 10, stains, coloring, and the like were not observed. However, since the surface roughness was coarse, a Mg alloy plate having a poor metallic texture was obtained. Further, the samples N〇 14 and 15' exceeding the surface roughness range were stained, colored, and the like, but the stains, coloring, and the like were inconspicuous, but a Mg alloy plate having poor metallic properties was obtained. As described above, after the honing process, if the liquid adhering to the surface of the Mg alloy sheet is not removed, the stain, the coloring, and the like become conspicuous, and when the surface processing method of the present invention is carried out, the stain, the coloring, and the like can be easily generated. . In particular, when the surface roughness of the above range is extremely small, when the surface processing of the present invention is carried out, a Mg alloy sheet having excellent metal texture without causing stains, coloring, or the like can be obtained. This is because the surface processing method of the present invention in the first and second embodiments can quickly remove the liquid that is in contact with the surface of the Mg alloy sheet during the processing. Therefore, the time during which the Mg alloy sheet is in contact with the liquid can be shortened, and the film can be suppressed. Corrosion of Mg alloy sheets and liquids. Further, the above-described embodiment can be modified as appropriate without departing from the technical scope of the present invention, and is not limited to the above configuration. [Industrial Applicability] The surface processing method of the Mg alloy sheet of the present invention can be utilized when the surface of the Mg alloy sheet is to be wet honed to be smooth. BRIEF DESCRIPTION OF THE DRAWINGS Fig. 1 is a schematic view for explaining a surface processing method of the first embodiment. Fig. 2 is a schematic view for explaining the surface processing method of the second embodiment. [Description of main component symbols] S: Roller W is repeatedly fed: Mg alloy plate 1: Honing process 1A, 10, 11: Honing belt 12: Spray nozzle 1 3: Honing fluid 2: Washing process 2〇: Washing Net nozzle 21: cleaning liquid 3: water removal process 3 〇: water removal roller 4: drying process 4 〇: air supply port 41: air 5: liquid removal process 50: liquid removal roller E: winding roller -23 -