Sebuah Kajian Pustaka: JEMMME (Journal of Energy, Mechanical, Material, and Manufacturing Engineering) Vol.5, No. 2, November 2020 ISSN 2541-6332 | e-ISSN 2548-4281 Journal homepage: http://ejournal.umm.ac.id/index.php/JEMMME Harsito | The Effect of RPM Stirrer Variation on Violence and Thickness of A36… 47 The Effect of Agitation Parameter on Hardness and Thickness of Decorative Nickel-Chrome Coating on A36 Steel using Electroplating Process Akmal Hanif Khairullah Harsitoa, Iis Siti Aisyahb, Daryonoc, Ali Saifullahd, Heni Hendaryatie, Sudarmanf a,b,c,d,e,fMechanical Engineering, Engineering Faculty, University of Muhammadiyah Malang Raya Tlogomas No.246, Malang, East Java, Indonesia (0341) 464318-319 e-mail: akmalhanif02@gmail.com, siti@umm.ac.id, daryono@umm.ac.id Abstract Electroplating is a process of settling substances (metal ions) on the electrodes (cathodes) by means of electrolysis. The occurrence of a precipitate in this process is due to the presence of electrically charged ions moving from an electrode through the electrolyte, the result of the electrolyte will seal on another electrode (cathode). During the process of deposition/deposit takes place a chemical reaction occurs at the electrode and electrolyte both reduction in a certain direction permanently, therefore it requires direct current and a constant voltage. Metal coatings commonly used are copper, nickel, chromium and others. Electroplating is basically to coat the metal to make it look more attractive and protected from corrosion, and can increase the product's resistance to friction. The purpose of this study was to determine the effect of stirrer rpm variations on the thickness and thickness of the A36 steel layer in the decorative nickel-chrome electroplating process. 4 specimens in this study were 30x30x2 (mm). Nickel and chromium coatings have variations in the speed of 72, 102, 132 and 162 (rpm) with a time immersion of 22 minutes and with a temperature of 55-60 ° C. The results of this electroplating process were tested by Vickers hardness test and observation of microstructure results. The results showed that the faster the rpm, the more hardness was obtained which increased and the thickness of the layer increased. The highest hardness and thickness values are found at a rotational speed of 132 rpm. With a hardness value of 77.5 VHN and a thickness value of 4.55 µm (Nickel) and 13.76 µm (Chrome). Keywords: Electroplating, Nickel, Chrome, rpm Stirrer, A36 1. INTRODUCTION We find almost every tool used by humans is made of metal, namely various jewelry, furniture, various crafts, motorcycle components, cars, and others. Some of the metals used are steel. Steel is divided into two parts, namely high carbon steel and low carbon steel. One of the low carbon steels is A36 steel. Weaknesses of this steel besides being easily corroded are also gray, unattractive, to prevent corrosion as well as to enhance the appearance, plating/coating is carried out. The main function of the metal coating is to improve the appearance (decorative), also improve the smoothness or surface shape and tolerance of base metals, and also can increase product resistance to friction (abrasion)[1]. In decorative applications, the solution used mostly nickel-plated is often applied in combination with chrome [2]. Electroplating or commonly called chrome serves to coat the metal to make it look more attractive and protected from corrosion. Until now, coating with electroplating has become a trend both in general use and in special uses such as medical equipment. Electroplating coating has a higher hygiene compared to oil paint or sprays paint, this has become one of the references regarding medical circles who use metals with a chrome coating. Niko Rensen's research states that with the presence of several factors that affect the coating such as the thickness of the coating, the morphology of the coating, the type of material used, time, temperature, and the displacement of the atom itself. Therefore it is http://ejournal.umm.ac.id/index.php/JEMMME mailto:akmalhanif02@gmail.com mailto:siti@umm.ac.id mailto:daryono@umm.ac.id JEMMME (Journal of Energy, Mechanical, Material, and Manufacturing Engineering) Vol.5, No. 2, November 2020 Harsito | The Effect of RPM Stirrer Variation on Violence and Thickness of A36… 48 necessary to use tools that affect the movement of atoms, one of which is with the help of magnetic stirrers [3]. By using a magnetic stirrer using magnetic field rotation to rotate the stir bar, the coating process occurs faster so that the thickness of the coating on the specimen is harder compared to without a magnetic stirrer. Chrome is the finish for the nickel decorative-protective plating system. The color is bluish-white and brilliant, resists tarnish (stain), resists corrosion, resists wear and scratches, and better protects the substrate [4]. Then research [5] revealed that the influence of surface roughness and stirring speed on the characteristics of the Ni-P non-metal layer. The experimental parameters varied, namely surface hardness of 0.044 μm, 0.056 μm, 0.101 μm, and 0.164 μm and stirring speed of 4.9 rpm, 11.3 rpm, and 21.3 rpm. The results of the study showed that the coarser surface of the substrate and the faster the stirring the larger the particle size of the formed layer, but not uniformly coated the entire surface of the substrate. The rougher the surface is and the faster the stirring is, the thicker the layer is formed, which is indicated by the payment of the electron microscope (SEM). From this research, research about the effect of RPM stirrer variations on the hardness and yield of A36 steel microstructure in the decorative nickel-chrome electroplating process. Since many application of electroplating products depend on the surface characteristic such as corrosion resistance and wear then it is need to do some experiment to investigate it especially on the hardness and thickness of electroplating. Also, the formation of compound of electroplating involves very complex mechanism so that make a change in one parameters will have influences on the product. 2. METHODS In this research, a decorative nickel-chrome electroplating process will be carried out. with a dipping time of 22 minutes and the anodes used are pure nickel and lead. The test that will be carried out in this research is the vickers hardness test which uses a diamond pyramid indenter which is a square shape [6] and a thickness test to find out how thick the layer is attached to the specimen. This research took place on 22 June 2020 to 24 June 2020. The research process can be seen in the flowchart below. Figure 1. Procedure and Methods Start Literature Review Research Preparation Electroplating Process Giving variations in speed, namely 72 rpm, 102 rpm, 132 rpm, and 162 rpm Hardness and Microstructure Testing Test Result Data Processing Analysis and Discussion Finish Conclusion Unclear Results Results Clear JEMMME (Journal of Energy, Mechanical, Material, and Manufacturing Engineering) Vol.5, No. 2, November 2020 Harsito | The Effect of RPM Stirrer Variation on Violence and Thickness of A36… 49 3. RESULT AND DISCUSSION 3.1 Hardness test results and thickness results of the chrome-nickel electroplating process For the results of hardness using Vickers hardness test equipment and for thickness using applications that are connected to the microstructure test equipment. a. Hardness test result (a) Without Coating (b) 72 rpm (c) 102 rpm (d) 132 rpm (e) 162 rpm Figure 2 Hardness Test Result b. Thickness coating result (a) 72 rpm (b) 102 rpm (c) 132 rpm (d) 162 rpm Figure 3 Thickness Coating Result JEMMME (Journal of Energy, Mechanical, Material, and Manufacturing Engineering) Vol.5, No. 2, November 2020 Harsito | The Effect of RPM Stirrer Variation on Violence and Thickness of A36… 50 3.2 Data Analysis and Discussion of Electroplating Nickel-Chrome Decorative 3.2.1 Data Analysis and Discussion of Hardness Test Electroplating Nickel-Chrome Decorative a. Without Coating Graphic 1. Hardness Value Without Coating Based on the graphic 1, it can be analyzed that at point 1 the hardness value is 20.60 VHN, point 2 the hardness value is 24.25 VHN, point 3 is the hardness value of 17.83 VHN, point 4 is the hardness value of 20.26 VHN, and point 5 is the hardness value of 23, 07 VHN. Visually seen a fluctuating value in the Vickers hardness test results. The lowest value obtained at point 3 and the highest value obtained at point 2. b. Variation Speed of 72 rpm Graphic 2. Hardness Value Average Speed of 72 rpm Based on the graphic 2, it can be analyzed that at point 1 the value of violence is 66.48 VHN, point 2 the value of violence is 64.91 VHN, point 3 the value of violence is 43.48 VHN, point 4 the value of violence is 20 VHN, and point 5 the value of violence is 51.09 VHN. Visually seen a fluctuating value in the Vickers hardness test results. The lowest value obtained at point 4 and the highest value obtained at point 1. Point 1 Point 2 Point 3 Point 4 Point 5 Uncoated Average VHN 20.60 24.25 17.83 20.26 23.07 0.00 5.00 10.00 15.00 20.00 25.00 30.00 H a rd n e s s V a lu e ( V H N ) Average VHN Without Coating Point 1 Point 2 Point 3 Point 4 Point 5 VHN has an Average Speed of 72 rpm 66.48 64.91 43.48 20.00 51.09 0 10 20 30 40 50 60 70 H a rd n e s s V a lu e ( V H N ) VHN Average Speed of 72 rpm JEMMME (Journal of Energy, Mechanical, Material, and Manufacturing Engineering) Vol.5, No. 2, November 2020 Harsito | The Effect of RPM Stirrer Variation on Violence and Thickness of A36… 51 c. Variation Speed of 102 rpm Graphic 3. Hardness Value Average Speed of 102 rpm Based on the graphic 3, it can be analyzed that at point 1 the value of violence is 86.38 VHN, point 2 the value of violence is 45.89 VHN, point 3 the value of violence is 32.73 VHN, point 4 the value of violence is 26.20 VHN, and point 5 the value of violence is 50, 56 VHN. Visually seen a decrease in value in the Vickers hardness test results. The lowest value obtained at point 4 and the highest value obtained at point 1. d. Variation Speed of 132 rpm Graphic 4. Hardness Value Average Speed of 132 rpm Based on the graphic 4, it can be analyzed that at point 1 the value of violence is 79.72 VHN, point 2 the value of violence is 87.58 VHN, point 3 the value of violence is 81.31 VHN, point 4 the value of violence is 98.78 VHN, and point 5 is the value of violence 40.11 VHN. Visually seen a fluctuating value in the Vickers hardness test results. The lowest value obtained at point 5 and the highest value obtained at point 4. Point 1 Point 2 Point 3 Point 4 Point 5 VHN has an Average Speed of 102 rpm 86.38 45.89 32.73 26.20 50.56 0 10 20 30 40 50 60 70 80 90 100 H a rd n e s s V a lu e ( V H N ) VHN Average Speed of 102 rpm Point 1 Point 2 Point 3 Point 4 Point 5 VHN has an Average Speed of 132 rpm 79.72 87.58 81.31 98.78 40.11 0 20 40 60 80 100 120 H a rd n e s s V a lu e ( V H N ) VHN Average Speed of 132 rpm JEMMME (Journal of Energy, Mechanical, Material, and Manufacturing Engineering) Vol.5, No. 2, November 2020 Harsito | The Effect of RPM Stirrer Variation on Violence and Thickness of A36… 52 e. Variation Speed of 162 rpm Graphic 5. Hardness Value Average Speed of 162 rpm Based on the graphic 5, above it can be analyzed that at point 1 the value of violence is 102.49 VHN, point 2 the value of violence is 51.63 VHN, point 3 the value of violence is 30.27 VHN, point 4 is the value of hardness 22.75 VHN, and point 5 the value of violence is 31, 14 VHN. Visually seen a decrease in value in the Vickers hardness test results. The lowest value obtained at point 4 and the highest value obtained at point 1. f. Vickers Total Hardness Test Results Graphic 6. Vickers Total Hardness Test Result Based on the graphic 6, of the total Vickers hardness test results above, it can be analyzed that in specimens without layers the average hardness value is 21.2 VHN, at a speed variation of 72 rpm the average hardness value is 49.19 VHN, at a speed variation of 102 rpm the average hardness value 48.35 VHN, at a variety of speed 132 rpm the average hardness value is 77.5 VHN, and at a speed variation of 162 rpm the average hardness value is 47.65 VHN. Visually seen a decrease in value in the Vickers hardness test results. The lowest value is obtained in the specimen without layers and the highest value is obtained at a variety of speed 132 rpm. The rise and Point 1 Point 2 Point 3 Point 4 Point 5 VHN has an Average Speed of 162 rpm 102.49 51.63 30.27 22.75 31.14 0 20 40 60 80 100 120 H a rd n e s s V a lu e ( V H N ) VHN Average Speed of 162 rpm Point 1 Point 2 Point 3 Point 4 Point 5 Total Vickers Hardness Test Results 21.2 49.19 48.35 77.5 47.65 0 10 20 30 40 50 60 70 80 90 H a rd n e s s V a lu e ( V H N ) Total Vickers Hardness Test Results JEMMME (Journal of Energy, Mechanical, Material, and Manufacturing Engineering) Vol.5, No. 2, November 2020 Harsito | The Effect of RPM Stirrer Variation on Violence and Thickness of A36… 53 fall of the hardness value are caused by the existence of rotation, according to the existence of previous research which states that the decrease in the value of hardness is due to the increasing speed of stirring, the higher the likelihood of defects [7]. 3.2.2 Data Analysis and Discussion of Thickness Coating Electroplating Nickel- Chrome Decorative a. Variation Speed of 72 rpm Graphic 7. Coating Thickness at 72 rpm Based on graphic 7, the fluctuating results obtained in the nickel layer while the chrome layer has increased from each side. However, these results do not greatly affect the surface of the specimen that has been carried out electroplating process. Judging from the results of the graph above the value of the nickel layer at 72 rpm speed variations are 3,11 μm, 4,4 μm and 4,09 μm (nickel) and 12,32 μm, 13,36 μm, and 15,12 μm. The result of slight fluctuations in the value of the nickel layer is due to the initial surface of the steel before being coated not too flat or surface treatment is less than optimal. b. Variation Speed of 102 rpm Graphic 8. Coating Thickness at 102 rpm Based on graphic 8, the fluctuating results obtained in the nickel layer while the chrome layer has increased from each side. However, these results do not greatly affect Point 1 Point 2 Point 3 Nickel 3.11 4.4 4.09 Chrom 12.32 13.36 15.12 0 2 4 6 8 10 12 14 16 M ic ro m e te r Coating Thickness at 72 rpm Point 1 Point 2 Point 3 Nickel 4.09 4.05 4.27 Chrom 12.37 13.49 14.72 0 2 4 6 8 10 12 14 16 M ic ro m e te r Coating Thickness at 102 rpm JEMMME (Journal of Energy, Mechanical, Material, and Manufacturing Engineering) Vol.5, No. 2, November 2020 Harsito | The Effect of RPM Stirrer Variation on Violence and Thickness of A36… 54 the surface of the specimen that has been carried out electroplating process. Judging from the results of the graph above the value of the nickel layer at 102 rpm speed variations are 4,09 μm, 4,05 μm and 4,27 μm (nickel) and 12,37 μm, 13,49 μm, and 14,72 μm. The result of slight fluctuations in the value of the nickel layer is due to the initial surface of the steel before being coated not too flat or surface treatment is less than optimal. c. Variation Speed of 132 rpm Graphic 9. Coating Thickness at 132 rpm Based on graphic 9, above, the fluctuating results obtained in the nickel layer while the chrome layer has increased from each side. However, these results do not greatly affect the surface of the specimen that has been carried out electroplating process. Judging from the results of the graph above the value of the nickel layer at 132 rpm speed variations are 4,27 μm, 4,09 μm and 5,31 μm (nickel) and 12,32 μm, 14,19 μm, and 14,77 μm. The result of slight fluctuations in the value of the nickel layer is due to the initial surface of the steel before being coated not too flat or surface treatment is less than optimal. d. Variation Speed of 162 rpm Graphic 10. Coating Thickness at 162 rpm Based on the graphic 10, the fluctuating results obtained in the chrome layer while the nickel layer has decreased from each side. However, these results do not greatly affect the Point 1 Point 2 Point 3 Nickel 4.27 4.09 5.31 Chrom 12.32 14.19 14.77 0 2 4 6 8 10 12 14 16 M ic ro m e te r Coating Thickness at 132 rpm Point 1 Point 2 Point 3 Nickel 4.27 4.09 3.11 Chrom 13.95 12.26 13.49 0 2 4 6 8 10 12 14 16 M ic ro m e te r Coating Thickness at 162 rpm JEMMME (Journal of Energy, Mechanical, Material, and Manufacturing Engineering) Vol.5, No. 2, November 2020 Harsito | The Effect of RPM Stirrer Variation on Violence and Thickness of A36… 55 surface of the specimen that has been carried out electroplating process. Judging from the results of the graph above the value of the nickel layer at a speed variation of 162 rpm is 4,27 μm, 4,09 μm and 3,11 μm (nickel) and 13,95 μm, 12,26 μm, and 13,49 μm. The result of slight fluctuations in the value of the chrome layer is due to the initial surface of the steel before being coated not too flat or surface treatment is less than optimal. e. Graph of Average Coating Thickness For All Speed Variations Table 1. Table Thick Nickel Plating No Variation of Nickel Electroplating Rotation Speed Point Thickness 1 (µm) Point Thickness 2 (µm) Point Thickness 3 (µm) Thick Average (µm) 1. 72 rpm 3,11 4,4 4,09 3,86 2. 102 rpm 4,09 4,05 4,27 4,13 3. 132 rpm 4,27 4,09 5,31 4,55 4. 162 rpm 4,27 4,09 3,11 3,82 Table 2. Table Thick Chrome Plating No Variation of Chrome Electroplating Rotation Speed Point Thickness 1 (µm) Point Thickness 2 (µm) Point Thickness 3 (µm) Thick Average (µm) 1. 72 rpm 12,32 13,36 15,12 13,6 2. 102 rpm 12,37 13,49 14,72 13,52 3. 132 rpm 12,32 14,19 14,77 13,76 4. 162 rpm 13,95 12,26 13,49 13,23 Graphic 11. Average Value of the Whole Thickness Coating of Speed Variations Based on the graphic 11, the average value of the thickness of the entire variation of the velocity results obtained is quite fluctuating or ups and downs of a thickness value in various variations. While at 72 rpm and 102 rpm speed variations, the thickness value is added, this indicates that the plating results are attached to the steel specimen before electroplating and rotation per minute are obtained which is the quite optimal and efficient speed for 72 rpm 102 rpm 132 rpm 162 rpm Nickel 3.86 4.13 4.55 3.82 Chrom 13.6 13.52 13.76 13.23 0 2 4 6 8 10 12 14 16 M ic ro m e te r Average Value of The Whole Thickness Coating of Speed Variations JEMMME (Journal of Energy, Mechanical, Material, and Manufacturing Engineering) Vol.5, No. 2, November 2020 Harsito | The Effect of RPM Stirrer Variation on Violence and Thickness of A36… 56 electroplating with a magnetic stirrer. Meanwhile, variations of 132 rpm and 162 rpm occur quite fluctuating values, as evidenced by the thickness value of 132 rpm is 4.55 µm (nickel), 13.76 µm (chrome) and at a speed of 162 rpm, the thickness value is 3.82 μm ( nickel), 13.23 µm (chrome). In theory, the electroplating process works by moving the nickel-chrome ions that move to the specimen (cathode) coating [8]. This is also based on the results of throwing power on the ions contained in the electrolyte must be controlled with a rotation that should not be too fast [9]. Proven in the test results above the thickness value at 72 rpm and 102 rpm rotation variations experienced a fairly good graph change, an increase at 72 rpm rotation and a decrease at 102 rpm rotation, this is following the basic theory of electroplating. While variations in the rotation of 132 rpm and 162 rpm occur a fairly drastic change in value. It is caused by spinning too fast so that the anode ions moving towards the cathode become uncontrolled and the adhesion process is disrupted. It is possible that the surface of the specimen which should be coated by anode ions is not coated and the part that has been coated, is re-coated without seeing the uncoated part due to too fast a speed. 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