缓蚀率测定方法
Corrosion inhibitor test method
详情见: Q/ SHCG109-2017
Standard: Q/ SHCG109-2017
试剂与仪器：
Reagents and instruments
盐酸：分析纯,用于配制腐蚀液(警示：盐酸对皮肤或纤维有灼伤腐蚀)
Hydrochloric acid: Analytical grade, used for preparing corrosive solutions (Warning: Hydrochloric acid can cause burns and corrosion to the skin or fibers)
石油醚：60℃~90℃,分析纯(警示：石油醚易燃).
Petroleum ether: 60℃ - 90℃, analytical grade (Warning: Petroleum ether is flammable)
无水乙醇：分析纯(警示：无水乙醇易燃).
Anhydrous ethanol: Analytical grade (Warning: Anhydrous ethanol is flammable).
六亚甲基四胺(乌洛托品)：配成质量分数为0.5%水溶液.
Hexamethylenetetramine (urotropine) : Prepare a 0.5% aqueous solution by mass.
水：符合GB/T6682中三级水的要求.
Water: Complies with the requirements of Grade III water as stipulated in GB/T6682.
缓蚀剂：待测样品.
Corrosion inhibitor: Sample to be tested.
盐酸溶液：质量分数为10%(用于清洗挂片).
Hydrochloric acid solution: 10% by mass (for cleaning the hanging plates).
试片规格：35mm×10mmX2mm的20"碳钢(符合GB/T699-2015).
Test piece specification: 20" carbon steel of 35mm×10mm × 2mm (in compliance with GB/ T699-2015).
仪器和设备
Instruments and equipment
恒温水浴：或与之类似的试验仪器,温度控制精度为士0.5℃.
Constant temperature water bath: Or similar test instruments, with a temperature control accuracy of ± 0.5℃.
注：测定温度时温度计应在检定有效期内.
Note: When measuring temperature, the thermometer should be within the validity period of verification.
电子天平：最小分度值0.1mg.
Electronic balance: Minimum division value 0.1mg.
试验容器：烧杯或其他
Test container: beaker or others
实验步骤：
Test procedures:
试片的准备：对购置到的试片进行检查,试片应有编号,选择表面光滑无毛刺的试片.
Preparation of test pieces: Inspect the purchased test pieces. They should be numbered and select those with smooth surfaces and no burrs.
试片的预清洗：先用石油醚浸泡擦拭,后用无水乙醇清洗,吸干,置于干燥器中保存 24h备用.测定前称量,准确至0.1mg,不应用手直接接触钢片表面.
Pre-cleaning of the test piece: First, soak and wipe it with petroleum ether, then clean it with anhydrous ethanol, absorb the moisture, and store it in a desiccator for 24 hours for future use. Weigh accurately to 0.1mg before measurement. Do not touch the surface of the steel sheet directly with your hands.
腐蚀溶液的制备：在20℃±2℃条件下,制备足量的1000mg/LHCl水溶液
Preparation of corrosion solution: At 20℃±2℃, prepare an adequate amount of 1000mg/LHCl aqueous solution
缓蚀样品溶液的准备：水溶性的缓蚀剂用蒸馏水稀释,配制成50mL~100 mL质量分数为10%的缓蚀剂溶液.
Preparation of the corrosion inhibitor sample solution: Dilute the water-soluble corrosion inhibitor with distilled water to prepare a 50mL to 100 mL corrosion inhibitor solution with a mass fraction of 10%.
采用四个试验容器,在四个实验容器中分别加入1000mg/LHCl水溶液做为腐蚀液,其中两个试验容器用作空白腐蚀试验,在另两个实验容器中加入缓蚀剂,使腐蚀溶液中缓蚀剂浓度为100mg/L.
Four test containers were used. 1000mg/LHCl aqueous solution was added to each of the four test containers as the corrosion solution. Two of the test containers were used for blank corrosion tests, and corrosion inhibitors were added to the other two test containers to make the concentration of corrosion inhibitors in the corrosion solution 100mg/L.
当温度稳定在85℃±2℃时,把准备好的装有腐蚀溶液(1000mL)的试验容器放入水浴中,每个试验容器中置入三片待测试片,试片悬挂的位置水平面角120°分布,试片在腐蚀液液面10mm下,且距离试验容器壁的水平距离不小于20mm,开始记录腐蚀测定时间.
When the temperature stabilizes at 85℃±2℃, place the prepared test containers containing the corrosive solution (1000mL) into the water bath. Put three test pieces in each test container. The test pieces should be suspended at a water plane Angle of 120°. The test pieces should be 10mm below the surface of the corrosive solution and at a horizontal distance of no less than 20mm from the wall of the test container. Start recording the corrosion determination time
试验开始后,若因温升引起水浴中水分蒸发量较大时(影响实验),应补充适量同温直至实验6h后结束,取出试片观察其表面情况并记录.
After the experiment begins, if the evaporation of water in the water bath is relatively large due to temperature rise (affecting the experiment), an appropriate amount of water at the same temperature should be supplemented until to the experiment ended after 6 hours. The test pieces were taken out to observe the surface condition and record it.
试片的处理：试片上腐蚀沉积物用质量分数为1O%HICI 溶液冲洗并再用脱脂棉蘸质量分数为0.5%乌洛托品水溶液(A.3.4)将试片擦洗干净,并用水冲洗干净;
The treatment of the test piece: The corrosion deposits on the test piece should be rinsed with 10% HICI solution by mass fraction, and then the test piece should be wiped clean with A cotton swab dipped in 0.5% urotropine aqueous solution (A.3.4) by mass fraction, and then rinsed clean with water.
最后用无水乙醇清洗后用滤纸吸干,置入干燥器 24h 后取出称量,准确至 0.lmg.
Finally, wash with anhydrous ethanol and dry with filter paper. Place in a desiccator for 24 hours, then take it out and weigh it accurately to 0.1mg.
注1：整个测定过程应在通风橱内进行.
Note 1: The entire measurement process should be carried out in a fume hood.
注2：在配制测定用腐蚀溶液的过程中应遵守国家对危险品的相关规定.
Note 2: During the preparation of corrosive solutions for determination, relevant national regulations on dangerous goods should be followed.
挂片腐蚀试验应在相同条件下做平行试验,每个试验容器内挂置三个试片.
The corrosion test of the hanging pieces should be conducted in parallel under the same conditions, with three test pieces hung in each test container.
测定结果的计算
Calculation of the measurement results
计算三个试片的平均腐蚀失重值
缓蚀率按下式计算：
n=(1-△Wx /△Wn)X100%
n-缓蚀率(%);
△Wx--加缓蚀剂条件下试片的腐蚀失重数值,单位为克(g);
△Wn--空白条件下试片的腐蚀失重数值,单位为克(g)
Calculate the average corrosion weight loss values of the three test pieces
The corrosion inhibition rate is calculated by the following formula:
n=(1-△Wx /△Wn)X100%
n - Corrosion inhibition rate (%);
△Wx - The corrosion weight loss value of the test piece under the condition of adding corrosion inhibitor, with the unit of grams (g);
△Wn - Corrosion weight loss value of the test piece under blank conditions, unit: grams (g)