27:
95:
182:
to rub or polish the metal's dull surface. Fine objects (such as silverware) may have the tarnish electrochemically reversed (non-destructively) by resting the objects on a piece of aluminium foil in a pot of boiling water with a small amount of salt or baking soda, or it may be removed with a
87:. Unlike wear patina necessary in applications such as copper roofing, outdoor copper, bronze, and brass statues and fittings, chemical patina is considered a lot more uneven and undesirable. Patina is the name given to tarnish on copper-based metals, while
150:; sometimes it is a metal sulfide. The metal oxide sometimes reacts with water to make the hydroxide, or with carbon dioxide to make the carbonate. It is a chemical change. There are various methods to prevent metals from tarnishing.
106:
on its reverse. While tarnishing on other metal objects is generally cleaned off, some toning on coins may be considered aesthetically pleasing or beneficial to the coin's value, and is therefore kept
76:
to tarnish, although it may tarnish with oxygen over time. It often appears as a dull, gray or black film or coating over metal. Tarnish is a surface phenomenon that is self-limiting, unlike
72:
as their outermost layer undergoes a chemical reaction. Tarnish does not always result from the sole effects of oxygen in the air. For example, silver needs
346:
291:
317:
221:
80:. Only the top few layers of the metal react. The layer of tarnish seals and protects the underlying layers from reacting.
395:
385:
299:
354:
266:
358:
303:
240:
26:
128:
83:
Tarnish preserves the underlying metal in outdoor use, and in this form is called chemical
8:
400:
175:
325:
217:
214:
Corrosion and corrosion control: an introduction to corrosion science and engineering
184:
131:
120:
162:
can prevent tarnish from forming over these metals. Tarnish can be removed by using
73:
390:
139:
20:
379:
103:
99:
88:
324:. Department of Chemistry, University of Wisconsin-Madison. Archived from
179:
171:
163:
183:
special polishing compound and a soft cloth. Gentler abrasives, like
167:
159:
147:
65:
61:
45:
57:
30:
192:
188:
135:
94:
84:
69:
49:
143:
124:
53:
34:
77:
267:"Coin Toning: Definition, Discussion and Effect on Value"
91:
is a term for the type of tarnish which forms on coins.
216:(4th ed.). Hoboken, N.J: Wiley-Interscience.
377:
212:Revie, R. Winston; Uhlig, Herbert Henry (2008).
187:, are often used by museums to clean tarnished
211:
153:
33:rods with evaporated crystals, partially
93:
25:
16:Corrosion on outer layer of some metals
378:
195:and will not leave unwanted residues.
191:as they cannot damage or scratch the
235:
233:
292:"Finishing techniques in Metalwork"
13:
102:demonstrating a colourful form of
14:
412:
264:
230:
339:
310:
284:
258:
205:
1:
198:
357:. 2011-06-02. Archived from
318:"Remove Tarnish from Silver"
114:
7:
10:
417:
300:Philadelphia Museum of Art
119:Tarnish is a product of a
19:For 1924 silent film, see
18:
351:ohiohistory.wordpress.com
396:Metalworking terminology
142:. It is usually a metal
355:Ohio Historical Society
154:Prevention and removal
111:
38:
158:Using a thin coat of
97:
37:with colorful tarnish
29:
322:scifun.chem.wisc.edu
44:is a thin layer of
386:Chemical reactions
241:"Guide to Tarnish"
112:
68:and other similar
39:
347:"Making it Shine"
271:The Spruce Crafts
223:978-0-471-73279-2
185:calcium carbonate
146:, the product of
121:chemical reaction
408:
370:
369:
367:
366:
343:
337:
336:
334:
333:
314:
308:
307:
302:. Archived from
288:
282:
281:
279:
277:
262:
256:
255:
253:
252:
237:
228:
227:
209:
74:hydrogen sulfide
48:that forms over
416:
415:
411:
410:
409:
407:
406:
405:
376:
375:
374:
373:
364:
362:
345:
344:
340:
331:
329:
316:
315:
311:
296:philamuseum.org
290:
289:
285:
275:
273:
263:
259:
250:
248:
239:
238:
231:
224:
210:
206:
201:
156:
117:
24:
17:
12:
11:
5:
414:
404:
403:
398:
393:
388:
372:
371:
338:
309:
306:on 2016-03-31.
283:
265:Bucki, James.
257:
229:
222:
203:
202:
200:
197:
155:
152:
140:sulfur dioxide
116:
113:
21:Tarnish (film)
15:
9:
6:
4:
3:
2:
413:
402:
399:
397:
394:
392:
389:
387:
384:
383:
381:
361:on 2012-03-23
360:
356:
352:
348:
342:
328:on 2018-04-01
327:
323:
319:
313:
305:
301:
297:
293:
287:
272:
268:
261:
246:
242:
236:
234:
225:
219:
215:
208:
204:
196:
194:
190:
186:
181:
177:
173:
169:
165:
161:
151:
149:
145:
141:
137:
134:, especially
133:
130:
126:
122:
109:
105:
101:
100:Morgan dollar
96:
92:
90:
86:
81:
79:
75:
71:
67:
63:
59:
55:
51:
47:
43:
36:
32:
28:
22:
363:. Retrieved
359:the original
350:
341:
330:. Retrieved
326:the original
321:
312:
304:the original
295:
286:
274:. Retrieved
270:
260:
249:. Retrieved
247:. 2019-08-14
244:
213:
207:
157:
118:
107:
82:
41:
40:
176:baking soda
172:emery paper
380:Categories
365:2012-10-19
332:2012-10-19
251:2024-08-17
245:Rio Grande
199:References
164:steel wool
123:between a
401:Corrosion
168:sandpaper
148:oxidation
115:Chemistry
66:neodymium
62:magnesium
46:corrosion
132:compound
129:nonmetal
58:aluminum
35:oxidized
31:Tungsten
276:1 April
108:in situ
42:Tarnish
391:Metals
220:
193:silver
189:silver
160:polish
136:oxygen
127:and a
104:toning
89:toning
85:patina
70:metals
50:copper
178:or a
144:oxide
125:metal
54:brass
278:2019
218:ISBN
180:file
138:and
78:rust
382::
353:.
349:.
320:.
298:.
294:.
269:.
243:.
232:^
174:,
170:,
166:,
98:A
64:,
60:,
56:,
52:,
368:.
335:.
280:.
254:.
226:.
110:.
23:.
Text is available under the Creative Commons Attribution-ShareAlike License. Additional terms may apply.
