the advantages of basalt glass flake coating for marine anticorrosion
TRANSCRIPT
The Advantages of Basalt Glass Flake Coating for Marine Anticorrosion
Huawu Liu1, a, Kaifang Xie1, Zongbin Yang2, Hongming Dai3
1Key Lab of Advanced Textile Composites, School of Textiles, Tianjin Polytechnic University,
Tianjin 300160, China
2Tianjin Silicate Institute, Tianjin 300111, China
3Tianjin Dingshang Technology Co., LTD, Tianjin 300384, China
Keywords: Igneous glass, Planar Flake, Marine Anticorrosion Coating.
Abstract. Harsh marine environment makes anticorrosion to be a technical challenge of ocean
engineering. Glass flake, as the pigment for under seawater coating, is required by anticorrosion
standard and has been the bottleneck of Chinese marine technology. Basalt planar glass flake is
novel anticorrosive pigment developed by the authors, which is environmentally friendly, strong,
heavy-duty anticorrosion, water impermeable, anti-weather and UV blocking and superior to the
traditional c-glass flake and basalt glass-ceramic flake. Epoxy resin has excellent properties of film
forming, corrosion resistance, low permeability, high adhesion and dimensional stable. Hence,
basalt glass flake reinforced epoxy resin coating has significant advantages in the marine
engineering, in terms of anticorrosion.
Heavy-duty anticorrosion is a challenge of Chinese ocean engineering
In 2008, Chinese Ministry of Land Resources reported that the crude oil reserves in the world were
183.9 billion tons and iron ore reserves were 233 billion tons. The current steel consumption in
China is 0.6 billion tons every year. Assuming a growth rate is 10% per year，the same as the GDP
of China, the accumulated steel consumption of China will be more than 100 billion tons in 2030.
Oil and steel, as the cornerstone of the second industrial revolution, will be exhausted in a couple of
decades. Human being will explore the ocean resources and there may or may not be another
option.
Ocean is a harsh corrosion environment, because of seawater oxidation, acid and alkali corrosion,
electrochemical corrosion, physical corrosion of wave impacting, biological corrosion of marine
organism and microorganism, weather aging caused by ultraviolet and so on, which is a technical
challenge of ocean engineering.
Advantages of epoxy resin coating reinforced by glass flake pigment
Coating is the simplest and most effective method of anticorrosion [1]. Standard NACE SP0108
requires that (aluminum sheet, glass, mica) flake must be adopted as pigment for under seawater
coating, since the resin matrix is permeable [2]. Among these flakes, glass flake is the dominant
pigment, due to its cost-effective and excellent anti-permeability attribute [3]. Glass flake coating
becomes the trend of marine heavy-duty (lifespan > 10 years) anticorrosion.
Advanced Materials Research Vols. 332-334 (2011) pp 1619-1622Online available since 2011/Sep/02 at www.scientific.net© (2011) Trans Tech Publications, Switzerlanddoi:10.4028/www.scientific.net/AMR.332-334.1619
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The advantages of glass flake pigment are listed as follows: 1) the zigzag path of corrosion
agents becomes longer than the straight one; 2) the boundary of the coating layer is partially
blocked; 3) the interior air bubbles are cut off; and 4) the way of crack extension is stopped (Fig. 1).
Water vapor permeability becomes 6-15 times less than that of the coating without flake and 4 times
less than that of the coating filled with fibers. In addition, flakes also contributions to low shrinkage
and thermal expansion [4,5]
1 2
3
4
Fig.1. The mechanisms of glass flack in anticorrosion.
Epoxy resin is a commonly used anticorrosion coating material. Among the epoxy resins,
bisphenol-A takes about 90% of the market, which is excellent for under seawater coating in terms
of adhesion bond, dimensional stability, low permeability, strong corrosion resistance and film
forming. Therefore, epoxy resin can be applied in various construction conditions, such as damp,
underwater, heating and so on. The weakness of epoxy resin is photoaging, but the UV radiation can
be blocked the black igneous flakes.
Novel planar flake made of basalt glass
In 1930s, Americans innovated glass flake and patented it 1941. The manufacturing method was
later replaced by rotating cup method [6,7]. In 2003, Ukraine developed basalt glass ceramic flake
containing 5% alkali oxides, whereas 30% of these alkali compositions insider of c-glass. It is
known that alkali oxides would weaken the physical and chemical properties, thus basalt glass
ceramic flake is far better for anticorrosion as shown in Table 1. In 2010, basalt glass was invented
in China, which is superior to c-glass and basalt glass ceramic in performances, lower price and
environmentally safe [8]. The continuous basalt glass fiber with rectangular cross-section was
developed by the innovators and such fibers can be crushed into planar flake [8].
Traditional flakes made in curved surface. The contact flakes may lead to air bubbles and reduce
permeability of the coating layer. With the increase of flake pigment, the water vapor penetration
goes down significantly at the beginning. When the weight ratio of glass flake exceeds 20%-30%,
water vapor penetration goes up with the increase of flake pigment [9, 10]. Less air bubbles are
formed by the contact planar flakes, thus more pigments are allowed to be add in and resulting in
better penetration resistance and dry shrinkage. Therefore, planar flake of basalt glass is the best
known pigment for heavy-duty anticorrosion in seawater.
1620 Advanced Textile Materials
Table 1. The properties of glass, basalt glass ceramic and basalt glass fibers [11-14]
Glass fiber Basalt glass ceramic fiber Basalt glass
fiber
Moh’s hardness 5.5-6 7 7.5
Tensile strength GPa 2.4 3 >3
Elastic modulus GPa 72 89 98
Anti-ultraviolet radiation No Yes Yes
Heat conductivity w/(m.k) 0.712-1.34 0.03-0.038 0.03
Low temperature resistance oC -200 -269 -269
Softening point oC 500-700 910 980
Cost Yuan/ton 3000-4000 0-8 Waste basalt
Sound absorption 80%-93% 90%-99% 90%-99%
Mass loss after 3h boiling in 2mol/L
NaOH 39% 2% 1.6%
Mass loss after 3h boiling in 2mol/L
HCl 6% 5% 4.2%
Epoxy coating enhanced by planar flake of basalt glass
Add flake pigment into the corrosion resistance resin to form the coating film and further apply
accelerant and initiator to build the entire coating with thickness around 500～1500µm. After the
removal of volatile materials, the resulting shrinkage may cause internal checks and pinholes in the
coating. In theory, basalt glass flake coating should contain as much as possible solid materials for
better dimensional stability. For curved flakes, the contact pieces may form an enclosed space and a
shortcut of the corrosion agents. When flakes are made in planar shape, no bubbles would be
formed between flakes, thus more solid pigments are allowed and few defects are developed after
the coating dries.
Epoxy coating enhanced with planar flake of basalt glass have excellent complementary
compositing effects, such as improved photoaging, enhanced penetration resistance and
significantly reduced dry shrinkage and internal defects, which makes the top cost-effective
combination for seawater anticorrosion coating. In addition, the combination also can be applied to
protect chemical plant, offshore platform, inner wall of tank, cross-sea bridge, harbor terminal, flue
gas desulfurization unit of power plant and so on.
Conclusions
The inland resources of the second industrial revolution will be exhausted, and human being will
certainly pursue natural resources in ocean. Harsh marine corrosion environment makes heavy-duty
anticorrosion coatings to be a technical challenge for ocean engineering. Flake pigment must be
applied to under seawater coating and so far c-glass flake coating has been the dominant materials
in marine heavy-duty anticorrosion market.
Marine coating requires photoaging resistance, penetration resistance and less dry shrinkage. The
black basalt flake is strong in UV protection, whereas the transparent c-glass is not able to provide
an expected weatherability. Moreover, in contrast to the traditional curved flake, the planar flakes
do not form any enclosed space. Therefore, more planar pigments are allowed as additives to reduce
the penetration of corrosion agents and defects resulting from the drying shrinkage.
Advanced Materials Research Vols. 332-334 1621
The epoxy resin enhanced by planar basalt glass flack is cost-effective and has excellent
performances in film forming, adhesion, low shrinkage, penetration and corrosion resistances,
which may be widely applied in marine and other heavy-duty anticorrosion conditions.
References
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[2] The National Association of Corrosion Engineers: SP0108. USA, (2008)
[3] G. Green, C. J. Watkinson: Proc. NACE 2004, No. 04011.(2004)
[4] D. Li et al: Fiber Composites. 1 (2): 45-47. (2000)
[5] W. Han et al.: Petroleum Engineering Construction. 31 (2): 64-67. (2005)
[6] US2251727 (1941)
[7] EP1732852B1, (2006)
[8] H.Dai, H. Liu, Z.Yang: CN2010078312 (2010)
[9] W.Zhang: Symposium of national bridge committee in 2007, 1014-1018.(2007)
[10] J. Wen: Journal of Dongguan University of Technology. 6 (1): 24-28. (1999)
[11] V. Fiore et al: Materials and Design, 2011, 32: 2091-2099.(2011)
[12] T. Deak: Textile Research J. 79 (7): 645-651. (2009)
[13] www.sudaglass.com.
[14] www.basaltfm.com.
1622 Advanced Textile Materials
Advanced Textile Materials 10.4028/www.scientific.net/AMR.332-334 The Advantages of Basalt Glass Flake Coating for Marine Anticorrosion 10.4028/www.scientific.net/AMR.332-334.1619