Investigating the Mechanism behind ‘Ant Nest’ Corrosion on Copper Tube

Situmorang, Riky Stepanus; Kawai, Hideki

doi:10.3390/ma11040533

Cited by 16 publications

(9 citation statements)

References 22 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Moreover, HCOOH is believed to cause ANC of copper tube more easily than any other carboxylic acids. [14][15][16] Cano et al [17][18][19] considered that except HCOOH, the higher the dissociation constant of a carboxylic acid is, the faster the corrosion rate of copper tube is. Zhou et al [20] believed that the interaction of ANC and stress corrosion caused the failure of copper tube.…”

Section: Introductionmentioning

confidence: 99%

An investigation on the mechanisms of ant nest corrosion of copper tube in formic acid environment

Liu

et al. 2022

Materials & Corrosion

View full text Add to dashboard Cite

Copper tubes used in air-conditioners and refrigerators often fail due to ant nest corrosion (ANC) in formic acid environment. In this paper, corrosion behavior and corrosion mechanisms of copper tubes in formic acid (HCOOH) were analyzed by vapor corrosion tests, optical microscopy (OM), scanning electron microscope (SEM), energy-dispersive X-ray spectrometry (EDS). The effects of the surface condition on ANC of copper tube were also investigated.Results showed that ANC of copper tube was a spontaneous process. The surface integrity of copper tube surface oxide layer is not the decisive factor of ANC. ANC originated from the dissolution of the surface oxide layer in HCOOH, which exposed fresh copper matrix. ANC is a special electrochemical corrosion, where the copper matrix acts as an anode and the undissolved surface oxide layer acts as a cathode due to the potential difference. The accumulation of corrosion products consisting of Cu(HCOO) 2 and Cu 2 O can produce a wedge effect and generate many microcracks until to penetrate the copper tube wall. These findings would provide a deep understanding of the corrosion behavior of copper and copper alloys.

show abstract

Section: Introductionmentioning

confidence: 99%

An investigation on the mechanisms of ant nest corrosion of copper tube in formic acid environment

Liu

et al. 2022

Materials & Corrosion

View full text Add to dashboard Cite

show abstract

“…Situmorang et al [ 16 ] reported that the corrosion rate of copper tubes in CH 3 COOH is the fastest in all carboxylic acids and the corrosion mechanisms of copper tubes in HCOOH are more complex. HCOOH is more likely to cause ANC of copper tubes.…”

Section: Introductionmentioning

confidence: 99%

“…[13,14] Besides stress corrosion, other corrosions induced by ions also contribute to the failure of copper tubes. [15] Situmorang et al [16] reported that the corrosion rate of copper tubes in CH 3 COOH is the fastest in all carboxylic acids and the corrosion mechanisms of copper tubes in HCOOH are more complex. HCOOH is more likely to cause ANC of copper tubes.…”

Section: Introductionmentioning

confidence: 99%

Comparison of the corrosion behavior of copper tubes in formic acid and acetic acid environment

Liu

Zhao

et al. 2021

Materials & Corrosion

View full text Add to dashboard Cite

Carboxylic acids with different carbon chains have different corrosion behaviors on copper tubes. In this paper, corrosion behavior and corrosion mechanisms of copper tubes in formic acid (HCOOH) and acetic acid (CH 3 COOH) were analyzed by vapor corrosion tests, electrochemical tests, contact angle examination, optical microscopy, Fourier transform infrared spectroscopy, and X-ray diffraction. The corrosion process of copper tubes in the HCOOH environment is more complex than in the CH 3 COOH environment and HCOOH is easy to cause "ant nest" corrosion on copper tubes. The corrosion rate is faster and the surface of the copper tube is more easily corroded in the CH 3 COOH environment due to the formation of unstable and loose corrosion products, Cu(OH)(CH 3 COO) 2 •2H 2 O. The results of the contact angle examination showed that the contact angles of HCOOH and CH 3 COOH on copper tube surface were 25°and 9°, respectively, which means that CH 3 COOH is more likely to be absorbed by the surface of the copper tube evenly. Differences in the wettability of these two carboxylic acids with copper tubes are the main reason for the different corrosion phenomena. The corrosion mechanisms of copper tubes in carboxylic acid are also discussed.

show abstract

“…It has been speculated that this form of corrosion, firstly described in the late '70s [5], causes approximately 10% of copper heat exchanger failures worldwide [7,8]. The corrosion pattern is characterized by microscopic tunnels (not noticeable by naked eye observation) that propagate randomly inside the tube wall, forming interconnecting longitudinal networks similar to an ant nest when observed in cross section [6,9,10]. Corrosion rate of this process is quite fast (10 mm/day at 0.3 mA cm -2 [11]).…”

Section: Introductionmentioning

confidence: 99%

“…Corrosion products filling the tunnels, mainly copper (I) oxide, may be transported on the tube surface [7]. It is commonly recognized that ant-nest corrosion of copper tubes is triggered by the simultaneous presence of air, moisture and carboxylic acids [7][8][9][10][11]. Some authors show that short-chain carboxylic acids can be originated from residual organic compounds (such as synthetic lubricant oils, degreasing or anti-tarnishing agents) [12][13][14], anthropogenic or biogenic processes [11], or even by decomposition of paints or hemicellose in the wood or hydrolysis of halocarbon refrigerants [13].…”

Section: Introductionmentioning

confidence: 99%