Surface treatment technologies. Ing. Petr Drašnar, Ph.D.

Transcription

1 Surface treatment technologies Ing. Petr Drašnar, Ph.D.

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3 Zn coatings Mechanism elektrochemical protection barrier protection Methods electroplating hot dip galvanizing thermal spray organic coatings /high content of Zn particles/ spec. methods galvanické zinkování

4 Electroplating Electroplating Electroless Plating Anodizing Coatings Etching and Chemical Milling Printed Circuit Board Manufacturing

5 Step 1 Ide ntify B ase M etal For Example: Steel, Cooper, Brass Step 2 Clean For Example: Degrease, Soak, & Electroclean Step 2R Step 3 Step 3R Step 4 Step 4R Step 5 Step 5R Step 6 Rinse A cid D e sca le & A ctiva te Rinse Pre-Plate (If required) Rinse Final Plate Rinse P ost T re atm en ts (As Specified) For Example: Hydrochloric, Sulfuric, or Fluoboric Acids. (Som e cases Peroxide Descale or Brite Dip For Example: Copper, Sulfamate Nickel, or Nickel If m ore tha n on e is specified Repeat Steps 4 & 4R as needed. For Example: Cadmium, Chromium, Copper, Gold, Lead, N icke l. S ilve r, S o ld e r, & Tin For Example: Chrom ates, Lacquers, & Seals Step 6R Rinse Step 7 Dry & Package For Example: Box or Hot Air Spin Dryers

6 Cleaning Only action is to remove dirt, oil, etc. from the top of the surface of the metal. Does not change the character of the actual metal surface or the color of the metal itself Often confused with phoshating Usually a 5 stage process: alkaline cleaning, rinse, phosphate, rinse, and sealer or chromating or sth.

7 Rinsing Generally rinsing is required after each (core or ancillary) process step. Removes chemicals from the previous process step that are lingering on the surface of the part, thus preventing cross contamination of process tanks.

8 Multi Stage Countercurrent Flow Rinse Work Flow Drain Water Flow

9 Electroplating Electroplating is the deposition of a metallic coating onto the surface of an object by putting a negative charge onto the object and immersing it into a solution which contains a salt of the metal to be deposited. Disociation of ZnSO4 to positive Zn 2+ and negative SO4 2- (acid electrolyte) ZnSO 4 Zn 2+ + SO4 2-

10 Galvanické zinkování

11 Electroless Plating Electroless plating is plating without the use of electrical energy a chemical reduction process which depends upon the catalytic reduction process of metal ions in an aqueous solution (containing a chemical reducing agent) and the subsequent deposition of the metal. Typical choice for irregularly shaped, highly detailed part shapes because of completely uniform deposit thickness and high precision.

12 Electroless Plating vs. Electroplating

13 Anodizing Anodizing is the electrochemical process by which the surface of a metal part is converted into a metal oxide Aluminum is the most common metal anodized Anodizing 1 Aluminum base metal 3 Aluminum oxide layer (Core #3) 5 Coloring matter

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21 Flame spray Electric Arc Thermal Spraying HVOF spraying Plasma spraying

22 Flame spray Arc spray

23 Materials ZINC wire 99,995% Zn ALUMINIUM To acid atmosphere, higher temperatures 600 C (automobile exhaust system). Wire 99,5% Al. ZINACOR Alloy of Zn (85%) + Al (15%)

24 Organic coatings Protection against corrosion atmosphere protective coatings Decoration color gloss structure texture Special properties antistatic, hydroizolation, high temperature Nátěrové hmoty

25 Organic coatings used for all materials in lot of appliactions Machining Industry Mining Industry, Oil Industry Chemical and Food Industry Civil Engineering Interior, Exterior Everywhere Nátěrové hmoty

26 Organic coatings Inside Outside Special /depends on purpose of coating and environment/ paint pigmented coating varnish nonpigmented coating Barrier protection Composition of paints bonding agent binder Solids fillers, pigments Liquid volatiles additives Substances producing visual effects Nátěrové hmoty

27 Organic coatings Organic coatings are applied by dip, brush and spray. Minimum labor cost by dipping. Dipping is common for applying protective coatings to forgings and castings to prevent rust during storage and processing and to serve as primers for the final finish. Many other products made in large quantities also are finished by dipping.

28 organické povlaky

29 Painting Brush painting is slow and used little in manufacturing work except on large, heavyor oddshaped parts that cannot be moved or manipulated in a spray paint area. Brushing and rolling are commonly used for coating structural surfaces such as walls and ceilings of buildings. By far the greatest amount of organic coatings are applied industrially by spraying. This method is used most with lacquers and fast drying enamels.

30 Painting Spraying is done in booths designed for this purpose where adequate ventilation carries fumes and spray particles away from the operator. For electrostatic spraying the paint particles are sprayed through a high voltage electrostatic field. Each paint particle takes on an electrical charge from the field and is attracted toward the grounded article to be pained. Better efficiency of paint use, distribution of paint over the entire object.

31 Aplicators Precise laboratory aplication Definition of thickness

32 HVLP SPRAY /high volume low pressure/, Airless Common used High productivity High quality

33 Electrostatic spray Higher efficiency Different thickness /surface, edge/

34 Powder coatings Charging of Powder Coatings Ectrokinetic, friction method, TRIBO method Electrostatic method high voltage electrode práškové nátěrové hmoty

35 Curing Furnace Polymeric reactions 160 C 200 C Time min. 60 to 100μm Powder coatings práškové nátěrové hmoty

36 Powder coatings práškové nátěrové hmoty

37 Termoplasts In past Low mechanical properties High price Termosets (reactoplasts) Common used Epoxide Polyester Epoxipolyest. Polyurethane Powder coatings práškové nátěrové hmoty

38 Recyclation of powder Vortex Powder coatings Filter práškové nátěrové hmoty

39 Powder coatings Positive forenvironment (without solvents) Very high utilization of material 100% Simple priciple High qualities corrosion protection, wear resistance Do additive drying Colour, structure, special effects práškové nátěrové hmoty

40 Metalisation and Org. Coatings in practise (duplex systeme)