[No.5/17] Which has greater efficacy, VCI paper vs. Rust preventive oil?
I have explained in the first column that there are many kinds of rust preventive oil, which reflects that there are so many different ways in use. I think there are so many cases among the usages of the rust preventive oil which can be replaced with VCI paper. About the VCI paper, I do hope you know correctly who are using the rust preventive oil.
I think I had better show the comparison of VCI paper with rust preventive oil so that you can get better knowledge and deepen understandings on both of them.
From this time, the series is divided into three, let me explain about which is more effective in view of a certain quality criteria for VCI paper and rust preventive oil when compared.
At first, I focus on the corrosion preventive performance. There are so many kinds both in VCI paper and rust preventive oil.
When comparing them on the whole without finely divided, you can get Table 3.
It indicates the performance is highly evaluated as far as the black mark is put on the left side in the field of evaluation. This is something roughly led by my personal experiences and knowledge, instead of making the evaluation based on the testing results.
(a) Although relative merits cannot be put in terms of “Corrosion preventive effect” since both are excellent, the merits might be confirmed depending on the actually used environment.
(b) In view of “Immediate performance”, the rust preventive oil will be better than the VCI paper.
Because the barrier effect is exercised as soon as oil film is formed in the case of rust preventive oil, while corrosion preventive effect is not performed until the corrosion inhibitor is vaporized from the VCI paper and reached to the target metal, in the case of the VCI paper requiring a little bit more time to perform the function.
(c) On the other hands, the VCI paper is superior in the performance for the parts with complicated shape.
Even if choosing low viscosity type-rust preventive oil, because of the surface tension of the oil as it is liquid, it is naturally difficult to get into the fine-grained holes and the every corner of the complicated shape metals. On the other hands, the corrosion inhibitor is gas form when vaporized, and can get into any fine place in the case of the VCI paper.
(d) In view of “Versatility”, the rust preventive oil is obviously superior after all.
The efficacy is not seriously varied depending on the type of metal, since the rust preventive oil is protecting the target metal with the barrier effect of oil film.
On the other hands, it cannot be said the VCI paper is always superior for whatever type of metals, because the target metal is chemically prevented from corrosion on the metal surface by the vaporized corrosion inhibitor in gas form, in the case of using VCI paper. It means that the VCI paper, which can match with the target metal, must be selected. If wrong choice was made, it may result corrosion on the contrary.