Subject: Seeking Expert Advice on Suitable Electrolyte Solution and Voltage Parameters for Pure Aluminum Electropolishing Study
Dear Research Community,
I hope this message finds you well. I am a student facing a critical issue that could potentially jeopardize my future. I am reaching out to seek your assistance or recommendations for someone who can help me overcome this challenge.
Currently, our research project focuses on the electropolishing of pure aluminum. However, we have encountered a significant obstacle that has impeded our progress. Our samples vary in size, with the maximum dimension being 0.5 cm.
In our study, we initially prepared the samples through sanding and subsequent polishing with powder. We have now reached the stage where we are ready to initiate the electropolishing process.
For the electrolyte solution, we have utilized a mixture of acids, including nitric acid, sulfuric acid, acetic acid, and ethanol. Initially, we created an electrolyte solution consisting of 25% nitric acid and 75% ethanol. The process was conducted at room temperature without employing a heater to raise the temperature. However, despite experimenting with voltage values ranging from 0 to 10 V, we have been unable to achieve desirable results. Instead, we observed the formation of H.
In a subsequent experiment, we modified the electrolyte solution by using 70% phosphoric acid, 15% acetic acid, and 5% nitric acid at room temperature. We increased the voltage to 20 V, resulting in a current density of 30. The electropolishing process was carried out for durations ranging from 30 seconds to 1 minute. Unfortunately, we encountered the same issue of excessive H production, leading to a completely white surface on our samples. We were unable to progress to the final stage of the process.
Additionally, we attempted to use the same electrolyte solution at 30 V for 10 seconds, but satisfactory outcomes were not achieved.
Given the aforementioned circumstances, I kindly request your professional advice regarding the appropriate electrolyte solution and voltage parameters for my future experiments.
Thank you in advance for your prompt response.
Yours sincerely,
Alireza Saravani
30% nitric acid and 70% methanol at −30 °C and 20 V keep in mind to stir the electrolyte, cooling can be done by pouring the liquid nitrogen on the electrolyte before electropolishing, if you have access to twin-jet electropolishing machine use it to obtain polarisation curve, remember to correctly connect the cables, counter electrode can be stainless steel.
I am most grateful for your esteemed advice, doctor. Would you kindly provide a thorough explanation regarding the permissible duration for remaining in the electrolyte solution?
Grzegorz Cios
It depends on the volume and stirring of the electrolyte; everything will slowly heat up. I suggest grinding the sample down to #2000 or #4000 SiC paper. Try 30 seconds to one minute.
Hello, we tried working with the following electrolyte: 700 mL ethanol (absolute), 120 mL distilled H2O, 100 mL 2-butoxyethanol, 80 mL HClO4 (60%). At a temperature of + 10 C, a voltage of 27-30 volts and a polishing time of 15-20 seconds, it was possible to obtain a polished surface on 5xx alloys and aluminum with a purity of 99.9%. For aluminum alloys 3xx and 4xx, the voltage was raised to 50 volts.
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