Metal Preparation 金属的处理
• Why Pretreatment ? 为什么要前处理？
• Powder coatings are used to enhance the appearance of buildings, machines, furniture, appliances: 粉末涂料用于改善建筑，机械设备，家具，以及其它器具的表面：
metal. 前处理是一种提高耐腐蚀的工艺
• Fe2 + O2 + H2O= RUST • Iron reacts with oxygen and water in the atmosphere
creating a powdery brown
mess, not very ornamental, and continuous until no solid metal remains. 铁在空气中会与氧气和水反应生成褐色的物质
• Metal pretreatment can be applied by spray or dipping. 金属前处理可以借助喷淋或浸渍
• In the case of iron phosphate the process could look like this: 下面是磷酸铁的工艺流程
Stages 1, 2 and 3 can be either spray or dip 步骤1，2和3均可采用喷淋或浸渍
Metal Pretreatment - BS 3189 Type 3
• 9 stage pretreatment 九步法
• Degrease脱脂 • Rinse水洗 • Rinse水洗 • Acid Etch (phosphoric acid)表调 • Rinse水洗 • Zinc Phosphate磷酸锌磷化 • Rinse水洗 • Rinse水洗 • De-ionised water去离子水水洗
Metal Preparation 金属的处理
• Molecules of water and salt can penetrate through the paint film.
• When they reach the metal surface the effect is worse than if the metal is uncoated.
• Iron Phosphate for Steel用于铁系的磷酸铁 • Zinc Phosphate for Steel用于铁系的磷酸锌
• Other systems can be used and information is available. 当然还有其它处理方法
前处理方式
• 前处理依据工件形式,可有三种处理流程:
• Designers and architects are searching to give distinction in terms of colour and effects. 设计师和建筑师提供了包括颜色和效果在内的标准等级
• The problem is that all paints are porous： 所有的涂料均不同程度的存在会渗水的小孔
• The performance of the powder coating is only going to be as good as the metal preparation.
We will cover two types of metal treatment systems 粉末涂料的功能类似于金属处理，我们将介绍两种的金属 处理方法
Metal Preparation – Zinc Phosphate 金属处理– 磷酸锌
• Zinc Phosphate process for steel tends to be more complicated 磷酸锌的工艺流程复杂一些
Metal Preparation 金属处理
• Dwell Time :Each stage depends on: 各阶段所需的时间，受下面的因素控制
• The metal then resists corrosion and the conversion permanently improves the
• adhesion of the coating. • 在使用粉末涂料以前用化学方法对金属表面进行处理，可喷淋:一般用于平板,死角少,形状单纯的工件,或速度
较快的喷涂线,如家电,天花板…等
• 浸渍:一般用于形状复杂,管件,死角多的工件,如家具
…等
• 游浸:此法为浸渍式的流水线作业方法,通常会搭配喷
淋式共同使用,如运动器材
Metal Preparation – Iron Phosphate 金属处理— 磷酸铁
• The answer = Pretreatment • 水和盐分子可以渗透漆膜，一旦它们与金属表面接触，产生
的影响甚至比没有喷涂还要糟糕。 • 要解决这个问题就需要前处理。
• Pretreatment: • 前处理：
• The chemical conversion of the metal surface before applying the powder coating.
POWDER COATING TRAINING
Metal Pretreatment for use with
Powder Coatings 金属前处理
Metal Preparation 金属的处理
• Pretreatment is a process intended to prevent the corrosion of the painted
• The amount of pretreatment chemical dissolved in water 溶于水的前处理化学药品的浓度
• The age of the chemical 化学药品的有效时间
• Regular checking is required to give consistent good results – at least twice per shift. 通常要经常检查前处理的状态—一个班至少两次